Method of producing desired organic compound via heterogeneously catalysed vapour-phase partial oxidation

FIELD: chemistry.

SUBSTANCE: method involves: a) heterogeneously catalysed vapour-phase partial oxidation of a starting organic compound selected from propylene, propane, isobutylene, isobutane, acrolein or methacrolein with molecular oxygen in a parallel-functioning system of oxidation reactors containing catalysts, which results in formation of two gas streams respectively containing the desired compound and respectively formed in one of two systems of oxidation reactors, and b) subsequent extraction of the desired product from two streams of the obtained gas to form at least one stream of crude desired product according to which c) before extraction of two from two streams, the obtained gas is mixed with each other into a mixed stream. In case of change in selectivity of formation of the desired product and/or by-products during operation the entire amount or partial amount of catalyst is replaced in parallel with fresh catalyst not in all parallel-functioning systems of oxidation reactors in which end products contained in the mixed stream are formed.

EFFECT: improved method of obtaining acrolein, acrylic acid, methacrolein or methacrylic acid as the desired product.

2 cl, 4 tbl, 2 ex

 

The present invention relates to a method for producing at least one target organic compounds

a) heterogeneously catalyzed vapor-phase partial oxidation of at least one source of organic compounds by molecular oxygen in at least two parallel operating systems reactor oxidation with you loaded catalysts, leading to the formation of at least two threads get gas, respectively containing the target compound and respectively formed in one of the at least two oxidation reactors, and

b) subsequent allocation of at least one target compound at least two threads get gas with the formation of at least one thread crude target product,

according to which

c) before allocating at least two of the at least two threads get gas, or in the process of allocating at least two containing the target product downstream, if necessary, formed during the transformation of at least two threads get gas in at least one stream of crude target product, and/or after discharge flows of crude target product, if necessary, formed in the process of allocating at least one of the two thread the received gas, mix with each other in the mixed stream.

In the context of the present description under the complete oxidation of organic compounds by molecular oxygen mean the transformation of organic compounds occurring during the reaction the effect of molecular oxygen, as a result of which the whole is contained in an organic compound carbon is converted to oxides of carbon, and the whole is contained in an organic compound hydrogen is converted into oxides of hydrogen.

Any different from the above transformations of organic compounds occurring during the reaction the effect of molecular oxygen, in the context of the present description is called the partial oxidation of organic compounds.

Thus, the term "partial oxidation" is used in the present description primarily to denote reactions partial ammoxidation, characterized in that the partial oxidation of organic compounds is carried out in the presence of ammonia.

In the context of the present description under partial oxidation should imply, in particular, such transformations of organic compounds occurring during the reaction the effect of molecular oxygen, which is subject to partial oxidation of an organic compound (the original organic compound) after which reversine contains at least one atom chemically bound oxygen more prior to the implementation of the partial oxidation.

In General it is known that the partial heterogeneously catalyzed oxidation of different raw organic compounds in the vapor phase with molecular oxygen allows to synthesize numerous chemicals. Examples of such syntheses can serve the transformation of tert-butanol, isobutene, isobutane, Isobutyraldehyde or simple methyl ether of tert-butanol in methacrolein and/or methacrylic acid (see, for example, German patent application DE-A 2526238, European patent application EP-A 092097, EP-A 058927, German patent application DE-A 4132263, DE-A 4132684 and DE-A 4022212), the transformation of acrolein in the acrylic acid, the conversion of methacrolein in methacrylic acid (see, for example, German patent application DE-a 2526238), the conversion of o-xylene and/or naphthalene into phthalic anhydride (see, for example, European patent application EP-A 522871), m-xylene to isophthalic acid, p-xylene into terephthalic acid or terephthalate, as well as conversion of butadiene to maleic anhydride (see, for example, German patent application DE-A 2106796 and DE-A 1624921), the conversion of n-butane to maleic anhydride (see, for example, application great Britain patent GB-A 1464198 and GB 1291354), transforming education acids corresponding to the above anhydrides, the conversion of propylene to acrolein and/or Krilova acid (see, for example, German patent application DE-A 2351151), the transformation of indianow, for example, anthraquinone (see, for example, German patent application DE-A 2025430), the conversion of ethylene to ethylene oxide or of propylene to propylene oxide (see, for example, German patent application DE-AS 1254137, DE-A 2159346, European patent application EP-A 372972, international application WO 89/0710, German patent application DE-A 4311608, and Beyer, Lehrbuch der organischen Chemie, 17th edition (1973)publishing Hirzel, Stuttgart, page 261), the conversion of propylene and/or acrolein in Acrylonitrile (see, for example, German patent application DE-A 2351151), the conversion of isobutylene and/or methacrolein in Methacrylonitrile, oxidative dehydrogenation of hydrocarbons (see, for example, German patent application DE-A 2351151), the conversion of propane to Acrylonitrile or acrolein and/or acrylic acid (see, for example, German patent application DE-A 10131297, European patent application EP-A 1090684, EP-A 608838, German patent application DE-A 10046672, European patent application EP-A 529853, international application WO 01/96270, German patent application DE-A 10028582), as well as conversion of ethane to acetic acid, benzene into phenol, 1-butene or 2-butene in the appropriate butandiol, and so on.

The lack of existing methods heterogeneously catalyzed vapor-phase partial oxidation of the source of organic compounds is the resulting gaseous products contain the target organic compound is not pure, and as a component of the mixture, which usually additionally contains by-products, neprevyshenie reagents and inert diluting gases (in accordance with the present description, dilution gas, which in the conditions of the heterogeneously catalyzed vapor-phase partial oxidation is characterized mainly inert behavior, we mean such gases, more than 95 mol%, preferably more than 99 mol%. each of the components in the conditions of the heterogeneously catalyzed vapor-phase partial oxidation remain chemically unchanged).

The target connection is subject to the allocation of such received gas (a mixture of gases obtained). With this purpose, the organic target compound, as a rule, first translated (if necessary after preliminary direct and/or indirect cooling) from the resulting gas mixture derived gases) in the condensed (liquid and/or solid) phase in suitable devices. Such transfer can be accomplished, for example, due to full or partial condensation of this gas. In the preferred embodiment, this translation is performed by the fractionation method of condensation (implemented, for example, in a column equipped with contributing to the separation of the embedded device; see, for example, German patent application DE-A 10332758 and cited it ur the level of technology).

According to another variant, the target compound can also be translated in the condensed phase by absorption of the optionally pre-cooled produced gas (a mixture of gases obtained), carried out suitable liquid absorbent in an absorption device (for example, absorption column equipped with contributing to the separation of an embedded device) (see, for example, German patent application DE-A 10336386, application for U.S. patent US-A 2004/0242826 and cited in these publications prior art). In addition, there is the possibility of transfer of organic target compounds from the resulting gas mixture derived gases) in the condensed phase adsorption of solid adsorbents or freezing.

Condensed phase or already contains the target connection (target product), which is necessary for its further application of purity (in this case, the condensed phase constitutes the desired flow of crude target product; however, the adjective "wet" means that the flow of the target product, along with the necessary target connection is typically further comprises analytically detectable amounts of at least one component that is different from the target product), or must be provided with a higher degree of purity of the raw stream Celje is on the product. In the latter case, the condensed phase forms only subsequent stream from which the necessary flow of crude target product can be obtained by using an additional, sequentially (one after another) are implemented, the known methods of selection. Such additional methods of selection, as a rule, are consistently implemented processes of extraction and/or distillation. Before application of additional methods for the isolation or in between if necessary, you can make steaming boiling products (under boiling products mean side components, the boiling point of which at normal conditions (at a temperature of 25°C and atmospheric pressure) below the boiling point of the corresponding target compounds). In addition, the implementation of these methods additional selection can contribute, carrying between them a separation by crystallization. Such methods of allocation of crystallization can also be only used additional methods of cleaning the condensed phase. Containing the target product material flow moving from one stage of separation (from one device to clear) to the next stage of the process (in the following treatment device), constitutes implied this is brilliant description of the corresponding subsequent flow. In the General case, the next subsequent flow at different stages of treatment (in other treatment device) from the previous subsequent thread that contains the target compound, which has a higher degree of purity.

Another feature of the synthesis of target organic compounds heterogeneously catalyzed vapor-phase partial oxidation of the source of organic compounds by molecular oxygen is that under the catalysts used to make such a synthesis, usually implies a rigid body.

Under the used catalysts especially often imply oxide mass or noble metals (e.g. silver). The catalytically active oxide weight along with the oxygen atoms can contain only one other element or more than one other element (multi-element oxide mass). As a catalytically active oxide masses especially often use products containing more than one elemental metal, especially transition metal. In this case we are talking about polymetallic oxide masses. Multi-element oxide mass usually are not simple physical mixtures of oxides of elemental components, and a heterogeneous mixture of complex prisoedinenii similar elements.

In addition, (primarily specified the s above) processes heterogeneously catalyzed vapor-phase partial oxidation is carried out at elevated temperature, component, typically a few hundred degrees Celsius, typically from 100 to 600°C.

Since most of the processes heterogeneously catalyzed vapor-phase partial oxidation is accompanied by high exothermic effect, to ensure optimal heat sink such processes are often carried out in a fluidized bed of a catalyst or reactor (usually refrigerated) with a fixed bed of catalyst, and the synthesis proceeds in the reaction space, around which circulates providing indirect heat transfer fluid (for example, the catalyst may be in the form of a stationary layer inside the contact tubes of the tubular reactor, washed provide heat salt melt).

However, the processes heterogeneously catalyzed vapor-phase partial oxidation, in principle, can be made in layers of catalyst under adiabatic reactors.

It is known that when implementation of the processes heterogeneously catalyzed vapor-phase partial oxidation operating pressure (absolute value) may be less than 1 bar, 1 bar or more than 1 bar. Working pressure typically is in the range from 1 to 10 bar, most often in the range of from 1 to 3 bar.

Transforming at least one source of organic compounds in General is Evoe connection (target transformation) occurs during the stay of the reaction gas mixture loaded in the reactor the catalyst, through which carry out transmission of the mixture.

Since most processes heterogeneously catalyzed vapor-phase partial oxidation of the source of organic compounds by molecular oxygen, usually wears a pronounced exothermic nature of the source reagents are usually diluted with mostly inert in the conditions of realization of the specified process gas, which because of its inherent heat capacity capable of absorbing heat.

One of the most commonly used inert dilution gas is molecular nitrogen, which is always automatically present in the reaction system, if the source of oxygen for heterogeneously catalyzed vapor-phase partial oxidation using air.

Other commonly used inert dilution gas is water vapor, because of its common availability. As the inert dilution gas is often used as recycled gas (see, for example, European patent application EP-A 1180508). Thus, in accordance with the above inert dilution gas used for the implementation of the most heterogeneously catalyzed processes vapor-phase partial oxidation of organic compounds, more than 90% vol., often more than 95% vol. consists of the zhota, water and/or carbon dioxide. This inert diluting gases, on the one hand, promote the absorption of heat of reaction, and on the other hand, ensure the safety of the implementation of the heterogeneously catalyzed vapor-phase partial oxidation of organic compounds due to the fact that the composition containing the reaction gas mixture is outside the explosive range. When heterogeneously catalyzed vapor-phase partial oxidation of unsaturated organic compounds in an inert diluting gases are often used as saturated hydrocarbons, i.e. flammable gases.

Heterogeneously catalyzed vapor-phase partial oxidation is often not carried in the same reactor, and in two or more series-connected reactors (which may also be located in a common casing and move from one to another without joints). As such serially connected reactors, oxidation, and oxidation reactors in the present description denotes the General term "system reactor oxidation". In the same way as an individual device or a personal device that is used to select at least one target compound from the resulting partial oxidation gas (gas mixture), and the sequence of these devices (the device is in for emphasis) in the present description is denoted by the term "allocation system". Neither the term "system reactor oxidation"nor the term "allocation system" does not imply parallel operation of forming these devices.

Thus, the sequence of system reactor oxidation (line reactors) and allocation system (processing line), which usually forms the production system (production line), designed to produce a target organic compounds heterogeneously catalyzed vapor-phase partial oxidation of at least one source of organic compounds by molecular oxygen. In the system of oxidation reactors source of the reaction gas mixture consisting of at least one source of organic compounds, molecular oxygen and at least one inert dilution gas, is passed at least through one fixed catalyst bed at elevated temperature and in the allocation system of the target compound isolated from the gas (gas mixture)obtained by partial oxidation in a stream of crude target product. If the allocation system consists of several series-connected with each other apparatuses (devices) for the allocation resulting from the partial oxidation gas (mixture of gases) forms a material flow directed to the first in trojstvo allocation system. Material flow emerging from the last unit allocation system is the flow of crude target product and material flows are transported within the system, the waste from one machine to another, form threads, which, as stated above, called subsequent threads.

System reactor oxidation, consisting of more than one reactor is used primarily in the case of partial oxidation is carried out in the form of a consistently implemented stages. In such cases, it is often appropriate optimization as catalyst and other reaction conditions for the corresponding reaction stages and implementation of the corresponding reaction stages in a separate reactor, respectively, in a separate reactor. A similar system reactor multi-stage oxidation using, for example, by the partial oxidation of propylene to acrylic acid. In the first reaction zone (in the first reactor for the first reaction stage) carry out the oxidation of propylene to acrolein, while in the second reaction zone of the second reactor to the second reaction stage) oxidize acrolein to acrylic acid. Similarly, two series-connected reaction zones (in two serially connected reactors), as a rule, the implementation of the designers and the synthesis of methacrylic acid, the reference compound for which often serves as isobutylene.

The reaction gas mixture between the two series-connected reactor system reactor oxidation, obviously, can be subjected to cooling and/or adding molecular oxygen (such as air and/or inert gas. However, both the above partial oxidation process can be performed also in the so-called dorectory systems, two series-connected reaction zones which are loaded with different catalysts are located within a single reactor, which in this case often has two temperature zones. However, both the above partial oxidation process using appropriate catalysts can be implemented in a single reactor with only one temperature zone.

In addition, with the aim of improving heat sink or other causes total transformation of the parent compound are often implemented in several series-connected reactors (see German patent application DE-A 19902562). In the corresponding typical variant proposed, for example, in German patent application DE-A 10 2004025445, processes heterogeneously catalyzed vapor-phase partial oxidation is carried out in tubular reactors.

The allocation system AKP is viewed acid, received heterogeneously catalyzed partial oxidation of propane and/or propylene, in the typical case consists of series-connected devices for direct cooling, absorption, and steaming, distillation columns (distillation columns) and, if necessary, the device (s) crystallization (see, for example, German patent application DE-A 10336386 and application U.S. patent US-A 2004/0242826).

To have the apparatus for selecting, in a constructive attitude are suitable for manufacturing large volumes of products, is relatively easy, whereas the availability of high performance reactors oxidation is limited. The reason for the limited availability of such reactors is that the processes heterogeneously catalyzed vapor-phase partial oxidation, as a rule, are of high ekzotermicheskie. A consequence of increased heat dissipation is the lack of sufficiently complete heat sink as productivity used for oxidation reactor.

Given the circumstances of the publication Process Economics Program Report No. 6C, Acrylic Acids and Acrylic Esters, SRI International, Menlo Park, California 94025 (1987), pages 1-40, to obtain acrylic acid proposed to use two parallel operating line reactors, each of which SOS is the RTO of two serially connected reactors: reactors intended to implement the first stage of the synthesis (propylene → acrolein), and reactors that are designed to implement the second stage of the synthesis (acrolein → acrylic acid). In this case we are talking about parallel operation of two systems connected in series reactors. The gas obtained in the same system of serially connected reactors, mixed gas obtained in the other parallel functioning system of serially connected reactors, after which the mixed flow is directed in General for both systems, reactor selection (processing line) the purpose of separation from it of acrylic acid. This technological option is proposed in international application WO 01/96271 (6), and in the German patent application DE-A 19902562 it is called classical parallel connection and also give examples of its implementation. Quoted above publication, Stanford research Institute (SRI) was also part of the official records regarding the protest against the European patent EP-700714 and EP-700893, and pretended to protest the face in the application of the U.S. patent US-A 2004/0242826 again trying to patent the classical parallel connection.

A disadvantage of the classical parallel connection, whereby loaded in the reactors of the two lines cut the catalysts begin to operate simultaneously and also simultaneously engaged in their subsequent operation, is that the selectivity of the formation as the target product and the products in the two reactor lines synchronously developing during the entire period of operation.

Such periods of operation catalysts for heterogeneously catalyzed vapor-phase partial oxidation, depending on the catalytic system and process of partial oxidation in typical cases range from several months to several years. Synchronous development of the selectivity of the formation of target and by-products on the respective catalysts during these periods of operation, characteristic of the parallel functioning of the reactor lines with the classical connection, is a disadvantage for the reason that during these periods the selectivity of the formation of both target and by-products, as a rule, does not remain unchanged. On the contrary, during this period in many cases is a decrease in the selectivity of formation of the target products and increasing the selectivity of side products formation. However, there are also situations where during the period of operation of the selectivity of the formation of the target product rises, while the selectivity of the formation of by-products decreases. This also applies to cases when in accordance with the recommendations, p is uvedenymi in the European patent applications EP-A 990636 and EP-A 1106598, the aging of the catalyst layer may try to resist, gradually increasing the operating temperature during operation while maintaining other operating conditions constant (which, as a rule, simultaneously causes the acceleration of the aging process of the catalyst) and/or from time to time by regeneration loaded in the reactors catalysts in accordance with the recommendations given in the European patent application EP-A 614872 and German patent application DE-A 10350822. The modification of the selectivity cannot be solved neither by replacing part of the catalyst, featured in the German patent application DE-A 10232748 or by varying the operating pressure recommended in the German patent application DE-A 10 2004025445.

However, changing the selectivity of the catalyst during the period of its operation requires a corresponding adaptation time performance line selection. In the case of low selectivity of side products formation can satisfactorily to allocate less costly method. In the case of the high selectivity of side products formation satisfactory solution to more complex tasks, their allocation requires the use of expensive line of the selection.

Thus, if during operation of the catalyst in the reactors with classic pairs relnum connection there is a change in the selectivity of side products formation, to get possessing the necessary degree of purity of the crude target product during the entire lifetime of the catalyst (up to its replacement) when constructing lines in the selection should focus on the maximum selectivity of the formation of side products during this period. That is, the selection should be as costly. This leads to the lower profitability of the target product. Based on the foregoing, the present invention was based on the task to offer specified in the beginning of the description of the method of obtaining at least one target organic compounds heterogeneously catalyzed vapor-phase partial oxidation of at least one source of organic compounds by molecular oxygen, which has a higher efficiency.

This task is solved through the method of obtaining at least one target organic compounds

a) heterogeneously catalyzed vapor-phase partial oxidation of at least one source of organic compounds by molecular oxygen in at least two parallel operating systems reactor oxidation with you loaded catalysts, leading to the formation of at least two streams developed the CSOs gas (a mixture of gases obtained), respectively containing the target compound and respectively formed in one of the at least two oxidation reactors, and

b) subsequent allocation of at least one target compound at least two threads get gas (a mixture of gases obtained) forming at least one thread crude target product,

according to which

c) before allocating at least two of the at least two threads get gas (a mixture of gases obtained), or in the process of allocating at least two containing the target product downstream, if necessary, formed during the transformation of at least two threads get gas (a mixture of gases obtained in at least one stream of crude target product, and/or after discharge flows of crude target product, if necessary, formed in the process of allocating at least one of the two threads get gas (a mixture of gases obtained), mix each with each other in mixed flow,

characterized in that

at least one of the catalysts loaded in at least two parallel operating system reactor oxidation, contains a partial amount of catalyst (preferably at least 20 wt%, respectively, of at least 40 wt%, better m is Nisha least 60 wt%, even better, at least 80 wt%, in terms of loaded catalyst, preferably at least all loaded catalyst), duration already implemented heterogeneously catalyzed vapor-phase partial oxidation in which more than all the parts of the at least one other of the loaded catalyst.

The number of reactor systems, functioning in parallel according to the invention in accordance with the proposed invention (we are talking about systems of oxidation reactors, in which education is contained in the mixed flow target compounds), usually is two. However, the number of such systems of reactors may also be three, four, five or more. In addition, the oxidation reactors in systems functioning in parallel according to the invention in accordance with the proposed invention, the method preferably have identical design. Hence, the reactor is preferably designed to produce the same volume of the target product and have the same design parameters. In the case of tubular reactors, this means that they typically contain mainly the same number with the same parameters of the contact tubes. The same applies to the principle of implementation of heat e is water.

However, the system of oxidation reactors, functioning in parallel according to the invention in accordance with the proposed invention is a method, in principle, can also be different from each other. In the case of tubular reactors it is, for example, about the difference as parameters (e.g., length, wall thickness, internal diameter, material), and the number of contact tubes. In addition, the parallel operating systems reactor oxidation according to the invention can be a system of totally different types. The source gas mixture flowing in the parallel functioning according to the invention the system of oxidation reactors,as a rule, are identical. That is, in the normal situation are the same as the composition and flow rate of gases flowing through the catalyst loaded in parallel functioning according to the invention the system of the oxidation reactors.

Therefore, for example, you can first generate a General flow of the source of the reaction gas mixture containing at least one of the original organic compound, which is then through the proper distribution system can be directed in at least two parallel operating system reactors (designed, for example, for the synthesis of acrylic acid partial oxidation).

According to the version in the operation of at least two parallel operating systems oxidation reactors typically use only one air compressor (which in some cases also select the required secondary air) and only one compressor is recirculated gas (according to the invention after separation of the target product preferably only recirculated gas) (preferred are centrifugal compressors according to the German patent application DE-A 10353014; compression recirculated gas and air can be done by two separate compressors, driven by two separate motors, by means of two compressors driven by a single motor, or by a single compressor driven by a single motor), however, according to the invention using only one air compressor (which in some cases also select the required secondary air) and only one compressor is recirculated gas is reasonable and if the source of the reaction gas mixture to each of the at least two parallel operating systems reactor oxidation spatial form independently from each other. In this case, compressed gases, for example, within the associated piping, refer to the appropriate static mixer where they are mixed with under appropriate pressure source organic compound, getting the original Rea the operating gas mixture, intended for introduction into an appropriate system of oxidation reactors.

While the intake of individual gases in the pipeline that feeds the static mixer, it is often appropriate to do so, in order to prevent the formation of explosive mixtures (in the case of partial oxidation of propylene, for example, acrolein and/or acrylic acid would, for example, first to produce the inlet recirculated gas and/or steam, then (raw) propylene and finally air). Then individually prepared source of the reaction gas mixture is sent to the at least two parallel operating systems reactor oxidation, which is designed to convert this source of the reaction gas mixture.

Under the flow (source) of the reaction gas mixture through the catalyst bed, designed to implement one or another reaction stage, in the context of the present description mean expressed in normal litres (nl) the amount of this gas mixture (volume (source) of the reaction gas mixture in liters, which it would in normal conditions, i.e. at 25°C and a pressure of 1 bar), passed through one liter of catalyst per hour. Consumption can also refer to only one component (source is s) of the reaction gas mixture. In this case we are talking about the number of such component, is passed through one liter of catalyst per hour (nl/l·h). When this bulk layers consisting only of inert material to the layer of catalyst do not apply.

The above applies also to the operating pressure and operating temperature in the parallel functioning according to the invention the system of the oxidation reactors. However, these individual parameters or groups of parameters (composition of the initial gas mixture (at the same initial connection and the same target product), the flow passed through the catalyst source organic compounds, respectively, of the reaction gas mixture, operating temperature, operating pressure)can obviously also be different from each other. The catalysts loaded in parallel functioning according to the invention the system of oxidation reactors, by type (i.e., chemical and physical parameters) are often identical (except for the differences due to different periods of their operation). However, in the parallel functioning according to the invention the system of oxidation reactors can be also downloaded the catalysts of various types.

An important feature of the invention consists in that at least one of the corresponding catalysts (we are talking about catalysis is the ora, used for the synthesis contained in the mixed flow target compounds)that are loaded in at least two parallel functioning according to the invention the system of oxidation reactors, contains at least part of the catalyst, the duration of the already implemented heterogeneously catalyzed vapor-phase partial oxidation in which more than all the parts of the at least one other of the loaded catalyst.

This peculiarity of the invention in accordance with a simple option can be implemented, for example, due to the fact that you first carry out simultaneous commissioning of at least two oxidation reactors, for example, with the same catalyst, introducing, for example, identical to the original gas mixture and using other identical reaction conditions, and then exploit the catalyst over an extended period. By reducing the selectivity of the formation of the target product as the operation of the catalyst, due to its aging (for example, when the decrease in the selectivity to the level that would have been impossible to extract crude target product with the required degree of purity), the above simple variant according to the invention can be implemented, for example, replacing a portion of the catalyst with fresh catalyst l is nil in one of the at least two parallel operating systems reactor oxidation, for example, in accordance with German patent application DE-A 10232748. You can then continue carried out according to the invention a parallel process. The selection of the target product is complicated only by the selectivity of the formation of a mixture of by-products, and it is possible to synthesize a crude target product with the desired degree of purity.

In this way it is possible without additional costs significantly prolong the service life of the loaded catalyst, which was not subjected to a partial replacement. Fresh catalyst, obviously, you can replace not only a part of one of the loaded catalysts, and all of this catalyst, after which you can continue the process according to the invention.

According to the invention, it is preferable to merge threads get gas (a mixture of gases obtained), leaving at least two simultaneously functioning according to the invention of systems of reactors, oxidation, mixed flow, which is then channelled to the first device for separation of the target product. However, in accordance with the proposed in the invention method, it is obvious, first, you can also parallel the selection of the target product, for example, like his synthesis of at least two parallel operating systems reactors. This option is preferred in those cases, e is whether the allocation system of the target product consists of several series-connected devices, only one of which is particularly capital-intensive or critical in some way. According to the invention may be useful parallel selection of the target product to especially capital-intensive (critical) system and only after this Association contains the corresponding target product subsequent flows in the mixed stream is sent forth in the above critical device. After this device if necessary, continue the parallel allocation of the target product is preferably ceased.

On the other hand, in accordance with the proposed invention by way of the selection of the target product can be run in parallel until the receiving thread crude target product. In this case, according to the invention are usually flows of crude target product with different content of impurities. While the content of impurities in one of these threads in some cases below the level of the regulated market in the specification, another thread crude target product impurities may not meet these requirements. By mixing similar threads to form a common stream crude target product that meets the regulated market of the specification requirements.

If carried out in accordance with izopet is of parallel operation of the three systems of oxidation reactors instead of uniting obtained in all three systems the flow of gas (gas mixture) and the subsequent processing of the mixture can also, for example, to merge two of these three streams and to process the mixture. The processing of the third stream can be managed separately, and then mix the mixture of the two flows of the target product with a third stream of the target product, and so on.

Different duration of operation of the catalyst loaded in at least two parallel operating system reactor oxidation, can be set, for example, due to the offset of the starting time of operation fresh loaded catalysts, and also due to the fact that loaded catalysts permanently or for a specified period of time operate at different temperatures and/or different costs of starting compound. Thus, a measure of the duration of operation of the loaded catalysts used only under the same conditions and with the same type of catalysts according to the invention is chronometerwerke time. Otherwise, measure the duration of the operation of catalysts is the number of already synthesized on it the target product. The greater the number of target product is synthesized on the catalyst, the more his age. In the case of multi-stage heterogeneously catalyzed vapor-phase partial oxidation occurring with education on ENISA least one intermediate product, a measure of the duration of the operation of the respective catalyst is the total number of already synthesized thereon intermediate product.

In the case of the two-stage synthesis of acrylic acid from propylene by the measure of the duration of operation of the catalyst used in the first reaction stage, serve, for example, the total number of already synthesized on it acrolein.

In the case of the two-stage synthesis of methacrylic acid from isobutylene measure the duration of operation of the catalyst used in the first reaction stage, serve, for example, the total number of already synthesized on it methacrolein. A measure of the duration of operation of the catalysts used in the second reaction stage of these processes, would serve as the quantity of acrylic acid, respectively, methacrylic acid, already synthesized on the respective catalysts.

Thus, in the case of multi-stage heterogeneously catalyzed vapor-phase partial oxidation of at least two parallel operating systems reactor after a certain duration of operation of the fresh catalyst replace at least part (preferably at least 20 wt. -%, better for men is our least 40 wt. -%, even better, at least 60 wt. -%, or at least 80 wt. -%, best of all 100% of the mass. in terms of loaded catalyst) of the catalyst, which is used on single phase oxidation of an appropriate system of reactors, oxidation, and then continue the process according to the invention. In the case of the two-stage synthesis of acrylic acid from propylene such partial or complete replacement may be subjected to the catalyst loaded in one of the at least two respective parallel operating systems reactor oxidation, and used only, for example, the reaction stage propylene → acrolein". However, such replacement can obviously also be subjected catalysts loaded in one of the at least two respective parallel operating systems oxidation reactors used in both reaction stages. In addition, according to the invention it is possible, in accordance with which the partial or complete replacement of the catalyst in at least one of the two considered in parallel operating systems reactor oxidation is carried out only for the first reaction stage, and another system of reactors such replacement carried out only for the second reaction stage.

In the case of increasing the CE is aktivnosti formation of the target product and the reduction of the activity of the loaded catalyst what is happening as its operation can be taken.

So, for example, at least two respective parallel operating system reactor oxidation loaded into each of them fresh catalysts at first for some time can be operated in the same conditions and mixed flow comprising at least two threads get gas, to send in a single allocation system. The allocation system can be calculated so that given the high initial selectivity of side products formation first to receive a stream of crude target product having a relatively low degree of purity. This thread may be, for example, the crude acrylic acid which can later be used only for the synthesis of complex alilovic esters (e.g. butyl, methyl, ethyl or 2-ethylhexanol of ester). In the case envisaged by the invention subsequent partial or complete replacement of the catalyst in the process of further operation of the catalyst reach the average level of selectivity of the formation of the target product, contained in a mixture of at least two relevant threads get gas, resulting in relatively high purity is obtained in the same system is adelene flow of crude target product. The flow of such a crude target product in this case can be, for example, raw acrylic acid, suitable for production of super absorbent polyacrylic acids, respectively, of the sodium salts.

Synthesized initially less pure crude acrylic acid, obviously, can also be stored in a large tank and mix it with later synthesized the crude acrylic acid, the content of impurities overlaps requirements specifications, receiving the mixture, which complies with the relevant requirements of the specification.

However, proposed in the invention method can also be used if at least two respective parallel operating system reactor oxidation loaded catalysts, the selectivity of the formation of the target compounds in the first of which as exploitation increases, while the second decreases. Thus, already after a short chronometerwerke duration of operation of at least two loaded catalysts they are formed of different amounts of the target product, and therefore, reach implied by the present invention "different" longevity is both loaded catalysts.

If implemented according to the invention a multi-stage heterogeneously catalizer the wow vapor-phase partial oxidation of at least one source of organic compounds, it is preferable to merge at least two parallel streams of gases, resulting from the first reaction stage, mixed flow (similar to practice classical parallel connection according to the German patent application DE-A 19902562) and subsequent implementation of the second reaction stage, at least two parallel operating systems reactor (after, if necessary, we add to the mixed stream of inert gas and/or molecular oxygen).

Proposed in the invention method is in principle suitable for the implementation of all specified at the beginning of the present description of specific processes heterogeneously catalyzed vapor-phase partial oxidation. Such processes primarily relates also described, for example, in international application WO 01/96270 and German patent applications DE-A 10316465, DE-A 10245585, DE-A 10246119 heterogeneously catalyzed vapor-phase partial oxidation of propane to acrylic acid. These publications, as well as the application of the U.S. patent US-A 2004/0242826 and German patent application DE-A 10336386 should be considered an integral part of this description. Proposed in the invention method is in principle suitable for heterogeneously catalyzed partial oxidation in a fluidized bed of a catalyst.

Heterogeneously catalyzed vapor-phase partial oxidation of at m is re one of the original organic compounds by molecular oxygen according to the invention preferably can be made of at least two concurrently active tubular reactors with co-current the reaction gas mixture in one of them and countercurrent in the other (if you look at the reactor top). The counter, as a rule, leads to accelerated aging of the catalyst, if it is used in identical conditions except for the direction of flow of the reaction gas mixture.

In accordance with the proposed invention by way of at least one of the catalysts loaded in at least two parallel operating system reactor oxidation, according to the invention should preferably include at least a partial quantity of the catalyst (in the case of multi-stage partial oxidation, for example, any number or part of the catalyst is intended to implement the first and/or second reaction stage), heterogeneously catalyzed vapor-phase partial oxidation which is carried out longer than all the other parts of the loaded catalyst, at least 30 calendar days, preferably at least 60, or at least 90 calendar days, particularly preferably at least 120, respectively, of at least 150 calendar days, even more preferably at least 180 calendar days, or at least 210, respectively 240 calendar days.

However, the proposed invention are also such with the person, in accordance with which the above difference in the duration of operation of the two catalysts is at least 270 days, at least 300 days, at least 330 days, at least 360 days, at least 400 days, at least 450 days, at least 500 days, at least 550 days, at least 600 days, at least 700 days, at least 800 days, at least 900 days, at least 1000 days at least 2000 days, or at least 3000 days, or it is more., as a rule, the corresponding difference is not more than three years, or 1000 days, usually not exceeding two years or 750 days.

This difference in the duration of the operation, expressed as a larger total amount of the target product, respectively, of the intermediate product synthesized at least part of the catalyst may be at least 106kg, at least 2·106kg, at least 3·106kg, at least 4·106kg, at least 5·106kg, at least 6·106kg, at least 7·106kg, at least 8·106kg, at least 9·106kg, at least 107kg, at least 1.5·107kg, at least 2·107kg, at least 3·107respectively 4·107kg, at least 5·107kg, m is Nisha least 6·10 7kg, at least 7·107kg, at least 8·107kg, at least 108kg, at least 2·108kg, at least 3·108kg or at least 4·108kg the above difference in the duration of operation generally corresponds to not more than 109kg, often less than 0.5·109kg and most often not more than 108kg synthetic product.

According to the invention is of great importance the fact that even slight changes in the selectivity of side products formation may complicate obtaining the crude target product that meets the requirements of the relevant specifications. A typical example in this regard can serve as propionic acid, present as a by-product of acrylic acid. For marketing opportunities acrylic acid it should contain, for example, not more than 800 million-1masses, propionic acid (the content of the latter depends on the scope of application of acrylic acid). A similar limit values are typical, for example, formed as by-products of formaldehyde and acetic acid. In many cases, the selectivity of the formation of the target product in the processes of heterogeneously catalyzed vapor-phase partial oxidation during the first three months after n the early operation of the loaded catalyst is modified by at least 0.1 or 0.2 mol%, or at least 0.3 or 0.5 mol%, accordingly, at least 1 or 1.5 mol%, accordingly, at least 2 mol%, sometimes even at least 3 mol%, at least 4 mol%. or at least 7 mol%.. Total selectivity of the formation of side components during the same period, as a rule, accordingly, often also varies by at least the amount of from 0.1 to 7 mol%. and more.

Therefore, in accordance with the proposed in the invention method, the difference in selectivity of the formation of the target product (e.g., acrylic acid) of at least two corresponding parallel operated loaded catalysts may be, for example, 7 mol%. or more (for example, it can be 0.1 or 0.2 mol%, or from 0.3 to 7 mol%), and the difference of the total selectivity of the education side components can also be 7 mol%. or more (for example, it can be 0.1 or 0.2 mol%, or from 0.3 to 7 mol%).

In a special variant proposed in the invention method is suitable for single-stage heterogeneously catalyzed in a stationary layer of vapor-phase partial oxidation of propylene to acrolein and/or acrylic acid, which is preferably carried out in a tubular reactor, as well as for the implementation of the first and second stage of two-stage heterogeneously catalyzer is imago vapor-phase partial oxidation of propylene to acrylic acid (via acrolein as an intermediate product) in the stationary layers of tubular reactors, for example, in accordance with the European patent applications EP-A 700893, EP-A 700714, German patent applications DE-A 19910508, DE-A 19910506, DE-AND 10351269, DE-A 10350812, DE-A 10350822, European patent application EP-A 1159247, German patent applications DE-A 10313208, DE-A 10 2004021764, DE-A 19948248, European patent applications EP-A 990636, EP-A 1106598 and German patent applications DE-a 3002829, DE-A 10232482.

Proposed in the invention method is suitable for the heterogeneously catalyzed in a stationary layer of vapor-phase partial oxidation of propylene to acrolein is primarily the case if the active mass of the catalyst is a multi-element oxide containing molybdenum and/or tungsten, and at least one element from the group of bismuth, tellurium, antimony, tin and copper, or a complex oxide containing molybdenum, bismuth and iron. According to the invention is particularly suitable for polymetallic oxide masses of the specified type containing molybdenum, bismuth and iron, are primarily active mass, described in the German patent applications DE-A 10344149 and DE-A 10344264. Primarily suitable are also active polymetallic oxide mass General formula (I) (DE-a 19955176), General formula (I) (DE-A 19948523), General formula (I), (II) and (III) (DE-A 10101695), General formula (I), (II) and (III) (DE-A 19948248) and General formulas (I), (II) and (III) (DE-A 199551680), as well as active polymetallic oxide mass, see what's in European patent application EP-A 700714.

In addition, the proposed in the invention method is suitable if at least two stationary layer used according to the invention for heterogeneously catalyzed vapor-phase partial oxidation of propylene to acrolein, contain polymetallic oxide catalysts containing molybdenum, bismuth and iron, are given in the German patent applications DE-A 10046957, DE-A 10063162, DE-C 3338380, DE-A 19902562, European patent application EP-A 15565, German patent application DE-C 2380765, European patent applications EP-A 807465, EP-A 279374, German patent application DE-A 3300044, European patent application EP-A 575897, the application of the U.S. patent US-A 4438217, German patent application DE-A 19855913, international application WO 98/24746, German patent application DE-A 19746210 (products of General formula (II)), Japanese patent application JP-A 91/294 239 and European patent applications EP-A 293224, EP-A 700714. We are talking primarily about the catalysts described in the respective examples, particularly preferred are catalysts of the European patent applications EP-A 15565, EP-A 575897 and German patent applications DE-A 19746210, DE-A 19855913. In this regard, it should be noted the catalyst from example 1C European patent application EP-A 15565, and obtained the same way catalyst, the active mass of which has the composition Mo12Ni6,5Zn2Fe2Bi1P0,006 K0,06Ox·10SiO2. In addition, it should be mentioned solid catalyst with the stoichiometric composition Mo12Co7Fe3Bifor 0.6K0,08Si1,6Oh) in the form of hollow cylinders with dimensions of 5 mm × 3 mm × 2 mm or 5 mm × 2 mm × 2 mm (external diameter × height × internal diameter) of example 3 of German patent application DE-a 19855913, as well as the whole complex oxide catalyst of the formula (II) from example 1 of German patent application DE-A 19746210. In addition, it should be noted polymetallic oxide catalysts described in the application U.S. patent US-A 4438217. Listed in this publication catalysts primarily suitable if they are hollow cylinders with dimensions of 5.5 mm × 3 mm × 3.5 mm, 5 mm × 2 mm × 2 mm, 5 mm × 3 mm × 2 mm, 6 mm × 3 mm × 3 mm or 7 mm × 3 mm × 4 mm (external diameter × height × internal diameter). In accordance with the present invention is also suitable for polymetallic oxide catalysts and their geometrical parameters specified in the German patent application DE-A 10101695, respectively the international application WO 02/062737.

In addition, in accordance with the invention are well suited solid catalysts with the stoichiometric composition [Bi2W2O9× 2WO3]0,5·[Mo12Co5,6Fe2,94Si1,59K0,08Ox]1example 1 German for the Cai patent DE-A 10046957, representing hollow cylinders (rings) with dimensions of 5 mm × 3 mm × 2 mm or 5 mm × 2 mm × 2 mm (external diameter × length × internal diameter)and the annular shell catalysts 1, 2 and 3 of German patent application DE-A 10063162 with the shell of the proper thickness with the stoichiometric composition Mo12Bi1,0Fe3Co7Si1,6K0,08)deposited on the annular carrier with dimensions of 5 mm × 3 mm × 1.5 mm or 7 mm × 3 mm × 1.5 mm (external diameter × length × internal diameter).

Many active polymetallic oxide masses, especially suitable as catalysts for the partial oxidation of propylene to acrolein, implemented proposed in the invention method, generally have the formula (I):

,

in which

X1mean Nickel and/or cobalt,

X2means thallium, an alkali metal and/or alkaline-earth metal,

X3mean zinc, phosphorus, arsenic, boron, antimony, tin, cerium, lead and/or tungsten,

X4means silicon, aluminum, titanium and/or zirconium,

a represents a number from 0.5 to 5,

b denotes a number from 0.01 to 5, preferably from 2 to 4

by means of a number from 0 to 10, preferably from 3 to 10,

d is a number from 0 to 2, preferably from 0.02 to 2,

E. means a number from 0 to 8, preferably from 0 to 5,

f oz is achet a number from 0 to 10 and

n means the number determined by the valency and frequency different from the oxygen elements in the catalysts of formula (I),

Such active polymetallic oxide mass can be obtained by known methods (see, for example, German patent application DE-A 4023239), and they are usually used in the form of a molded mass of balls, rings or cylinders, as well as shell catalysts, that is covered by the active mass of molded inert phone Similar mass, obviously, can be used as catalysts in powder form.

Active mass General formula (I) can be prepared by a simple method, consisting in the fact that you get thoroughly mixed, preferably fine dry mixture of the respective sources of the elements of the active mass, used in the appropriate stoichiometric ratio, and the resulting mixture is calcined at a temperature of from 350 to 650°C. the Calcination can be performed in the atmosphere of inert gas and oxidizing atmosphere such as air (mixture of inert gas and oxygen), and also in reducing atmosphere (for example, in a mixture of inert gas, ammonia, carbon monoxide and/or hydrogen). The duration of calcination can vary from several minutes to several hours, and usually it is being the et the shorter, the higher the temperature of annealing. As sources of active elements polymetallic oxide mass General formula (I) can be used compounds which are already oxides and/or compounds that can be converted into oxides by heating, carried out at least in the presence of oxygen.

Along with oxides such parent compounds primarily can be a halide, nitrate, formate, oxalates, citrates, acetates, carbonates, complexes of amines, ammonium salts and/or hydroxides (thoroughly mixed dry mixture can optionally type compounds such as NH4OH, (NH4)2CO3, NH4NO3, NH4CHO2CH3COOH, NH4CH3CO2and/or ammonium oxalate, capable of dissociation and/or degradation with release of gaseous products escaping at the latest during the subsequent calcination).

Thorough mixing can be subjected to the parent compound to obtain active polymetallic oxide mass General formula (I), under both dry and wet condition. In the case of dry mixing source compounds, they should be used in the form of fine powder, and after mixing and, if necessary, provide seals subjected to calcination. However, tatel the resultant mixing preferably is subjected to wet the parent compound. While the parent compound is usually mixed in aqueous solution and/or suspension. Especially thoroughly mixed dry mortars get a similar way in the case when the sources of elements of the active masses are exclusively in the dissolved form. The solvent preferably use water. The resulting aqueous mass is subjected to drying is preferably carried out in the spray dryer at a temperature output component from 100 to 150°C.

Active polymetallic oxide mass General formula (I) is usually used in a stationary catalyst bed is not in powder form and in the form received by the molding of the catalyst with certain geometrical parameters, and the molding can be performed before or after calcination. So, for example, having the desired geometric shape of the solid catalysts can be obtained by compacting a powder of the active mass or appropriate not subjected to annealing and/or subjected to partial annealing of the initial mass, implemented, for example, methods tabletting, extrusion or extrusion, and seal if necessary you can add to improve the sliding and/or facilitate molding AIDS such as graphite or steer the new acid, and reinforcing means, such as microfibers of glass, asbestos, silicon carbide or potassium titanate. Suitable geometric form of solid catalysts correspond, for example, solid or hollow cylinders having an external diameter and a length constituting from 2 to 10 mm, an Appropriate thickness of the walls of the hollow cylinders is from 1 to 3 mm Solid catalyst, obviously, can have the shape of balls, the diameter of which may range from 2 to 10 mm

Especially the optimal dimensions of the hollow cylinders (especially in the case of solid catalysts) are 5 mm × 3 mm × 2 mm (external diameter × length × internal diameter).

The molding powder of the active mass or corresponding powder of the initial mass, not subjected to annealing and/or subjected to partial annealing, obviously, you can also make its application to molded inert carrier for catalysts. The application of active mass on the molded body of the carrier with the aim of obtaining shell catalysts, as a rule, is carried out in a suitable rotating the tank, for example, described in German patent application DE-A 2909671 or European patent applications EP-A 293859 and EP-A 714700. Applied to the molded body of powdered media weight it is advisable to put moisture, and after application, drying, for example, Achim air. Suitable thickness of the applied layer of the powder mass is from 10 to 1000 μm, preferably from 50 to 500 μm and particularly preferably from 150 to 250 μm. In accordance with another variant of the powder mass can be applied to the molded body of the carrier directly from the corresponding suspension or solution (e.g. water).

The material of the carrier may be conventional porous or nonporous aluminum oxide, silicon dioxide, thorium dioxide, zirconium dioxide, silicon carbide or silicates such as magnesium silicate or aluminum silicate. In terms of the target reaction is carried out in accordance with the proposed invention the method, the first reaction stage, these materials behave as a rule, mostly inert. The pH of the media, you can make regular or irregular shape, and are preferred body media, with regular shape, for example, balls or hollow cylinders with a distinct surface roughness. Suitable are having a rough surface, mainly non-porous spherical body media from steatite (for example, product Steatit C220 CeramTec) with a diameter of from 1 to 8 mm, preferably from 4 to 5 mm are also Suitable body of the carrier in the form of a cylinder of length from 2 to 10 mm (for example, 8 mm) and outer di the meter from 4 to 10 mm (for example, 6 mm). If according to the invention is suitable bodies media are rings, in addition to these settings, they are characterized by thick walls, usually component from 1 to 4 mm, Preferably used according to the invention the annular body of the carrier have a length of from 2 to 6 mm, an external diameter of from 4 to 8 mm and wall thickness from 1 to 2 mm According to the invention as tenocytes primarily suitable rings with geometric parameters 7 mm × 3 mm × 4 mm, 5 mm × 3 mm × 2 mm (external diameter × length × internal diameter). The thickness of the layer of catalytically active oxide mass applied on the surface of the bodies of the media, obviously, should be in accordance with the required thickness of the shell (see European patent application EP-A 714700).

In addition, for a stationary layer of catalysts for partial oxidation of propylene to acrolein, implemented proposed in the invention method is particularly suitable active polymetallic oxide mass General formula (II):

,

in which

Y1means only bismuth or bismuth and at least one of the elements of the group tellurium, antimony, tin and copper,

Y2means molybdenum or molybdenum and tungsten,

Y3means of alkali metal, thallium and/or samarium,

Y4means y is lacno-land metal, Nickel, cobalt, copper, manganese, zinc, tin, cadmium and/or mercury,

Y5means iron or iron and at least one of the elements of the group chromium and cerium,

Y6mean phosphorus, arsenic, boron and/or antimony,

Y7means rare earth metal, titanium, zirconium, niobium, tantalum, rhenium, ruthenium, rhodium, silver, gold, aluminum, gallium, indium, silicon, germanium, lead, thorium and/or uranium,

and' means a number from 0.01 to 8,

b' denotes a number from 0.1 to 30,

with' means a number from 0 to 4,

d' denotes a number from 0 to 20,

e' refers to the number of from >0 to 20,

f' denotes a number from 0 to 6,

g' stands for a number from 0 to 15,

h' stands for a number from 8 to 16,

x', y' means the number determined by the valency and frequency different from the oxygen elements in the General formula (II), and

p, q means the number, the ratio (p/q) is from 0.1 to 10,

containing three-dimensional region with the chemical composition of the Y1a'Y2b'Ox', separated from the locally surrounding material with a different composition, the maximum diameter (longest line segment that passes through their center of gravity and connecting two points on the surface (boundary surface)) is from 1 nm to 100 μm, frequently from 10 to 500 nm or from 1 to 50, 25 μm, respectively.

Especially preferred are polymetallic ACS is derivative of the mass General formula (II), in which Y1only bismuth.

The latter are preferably polymetallic oxide mass General formula (III):

,

in which

Z2means molybdenum or molybdenum and tungsten,

Z3mean Nickel and/or cobalt,

Z4means thallium, an alkali metal and/or alkaline-earth metal,

Z5mean phosphorus, arsenic, boron, antimony, tin, cerium and/or lead,

Z6means silicon, aluminum, titanium and/or zirconium,

Z7means copper, silver and/or gold,

a" means a number from 0.1 to 1,

b" means a number from 0.2 to 2,

C" stands for a number from 3 to 10,

d" denotes a number from 0.02 to 2,

e" means a number from 0.01 to 5, preferably from 0.1 to 3,

f" means a number from 0 to 5,

g" means a number from 0 to 10,

h" means a number from 0 to 1,

x", y" means the number determined by the valency and frequency different from the oxygen elements in the General formula (III),

p", q" means the number, the ratio (p/q) is from 0.1 to 5, preferably from 0.5 to 2,

even more preferred are polymetallic oxide mass General formula (III)in which Z2bmeans (W)band Z212means (Mo)12.

In addition, preferably, when at least 25 mol%. (PR is doctitle at least 50 mol%, especially preferably 100 mol%.) the total number of [Y1a'Y2b'Ox']p([BiaZ2bOx"]pin suitable according to the invention polymetallic oxide masses of the General formula (II) (polymetallic oxide masses of the General formula (III)is present in these polymetallic oxide masses in the form of three-dimensional regions of the chemical composition of the Y1a'Y2b'Ox'[BiaZ2bOx"], distinct from that with other local composition of the surrounding material, and the maximum diameter of such three-dimensional regions is from 1 nm to 100 μm.

Forming polymetallic catalysts with oxide masses of General formula (II) perform similarly to the formation of polymetallic catalysts with oxide masses of General formula (I).

Preparation of active polymetallic oxide mass General formula (II) are described, for example, in European patent application EP-A 575897, as well as in the German patent applications DE-A 19855913, DE-A 10344149 and DE-A 10344264.

As the active mass of the catalyst used in at least one stationary layer of catalysts for partial oxidation of acrolein in acrylic acid according to the invention is suitable known containing molybdenum and vanadium complex is xidi, which is used to perform reactions of this type.

Similar containing molybdenum and vanadium active polymetallic oxide mass is given, for example, in applications U.S. patent US-A 3775474, US-A 3954855, US-A 3893951 and US-A 4339355, European patent application EP-A 614872, respectively, EP-A 1041062, or international application WO 03/055835, respectively WO 03/057653.

Primarily suitable active polymetallic oxide mass offered in the German patent applications DE-A 10325487 and DE-10325488.

In addition, as the active mass of the stationary layers of catalysts for partial oxidation of acrolein in acrylic acid is carried out in accordance with a special variation proposed in the invention method, suitable for polymetallic oxide mass is given in European patent application EP-A 427508, German patent applications DE-a 2909671, DE-C 3151805, DE-AS 2626887, DE-A 4302991, European patent applications EP-A 700893, EP-A 714700 and German patent application DE-A 19736105. In this regard, particularly preferred are active mass offered, for example, in European patent application EP-A 714700, as well as in the German patent application DE-a 19736105.

A lot of this kind containing molybdenum and bismuth active polymetallicity masses have the General formula (IV):

in which

X1means tungsten, niab the th, tantalum, chromium and/or cerium,

X2means copper, Nickel, cobalt, iron, manganese and/or zinc,

X3means antimony and/or bismuth,

X4means one or more alkali metals,

X5means one or more alkaline-earth metals,

X6means silicon, aluminum, titanium and/or zirconium,

a represents a number from 1 to 6,

b denotes a number from 0.2 to 4,

by means of a number from 0.5 to 18,

d is a number from 0 to 40,

E. means a number from 0 to 2,

f denotes a number from 0 to 4,

g denotes a number from 0 to 40 and

n means the number determined by the valency and frequency different from the oxygen elements in the General formula (IV).

According to the invention are preferred active polymetallic oxides of General formula (IV), in which

X1means tungsten, niobium and/or chromium,

X2means copper, Nickel, cobalt and/or iron,

X3means antimony,

X4mean sodium and/or potassium,

X5mean calcium, strontium and/or barium,

X6means silicon, aluminum and/or titanium,

a represents a number from 1.5 to 5,

b denotes a number from 0.5 to 2,

by means of a number from 0.5 to 3,

d is a number from 0 to 2,

E. means a number from 0 to 0.2,

f denotes a number from 0 to 1, and

n means the number determined by the valence and overemotionalize from oxygen elements in the General formula (IV).

According to the invention is even more preferred polymetallic oxides of the General formula (IV) are those which have the General formula (V):

,

in which

Y1means tungsten and/or niobium,

Y2mean copper and/or Nickel,

Y5mean calcium and/or strontium,

Y6means silicon and/or aluminum,

and' means a number from 2 to 4

b' denotes a number from 1 to 1.5,

with' means a number from 1 to 3,

f' denotes a number from 0 to 0.5,

g' stands for a number from 0 to 8 and

n' means the number determined by the valency and frequency different from the oxygen elements in the General formula (V).

Active polymetallic oxide mass General formula (IV) can be obtained by the known methods described, for example, in German patent application DE-A 4335973 or European patent application EP-A 714700. However, according to the invention as containing molybdenum and vanadium active polymetallic oxide masses intended for partial oxidation of acrolein in acrylic acid, especially suitable active mass, proposed in the German patent application DE-A 10261186.

In principle, such containing molybdenum and vanadium active polymetallic oxide mass primarily of General formula (IV) can be prepared by a simple method, with the standing in what do you get as much as possible thoroughly mixed, preferably fine dry mixture suitable sources of the elements, which has a corresponding stoichiometric composition, and subjecting it to calcination at a temperature of from 350 to 600°C. the Calcination can be performed in the atmosphere of inert gas and oxidizing atmosphere such as air (mixture of inert gas and oxygen), and also in reducing atmosphere (for example, in mixtures of inert gas and reducing gases such as hydrogen, ammonia, carbon monoxide, methane and/or acrolein, or specified individually used regenerating gases). The duration of calcination can vary from several minutes to several hours, and usually it is the shorter, the higher the temperature of annealing. As sources of the elements that make up the active polymetallic oxide mass General formula (IV), it is possible to use compounds which are already oxides and/or compounds that can be converted into oxides by heating, carried out at least in the presence of oxygen.

Thorough mixing can be subjected to the parent compound to obtain active polymetallic oxide mass General formula (IV)under both dry and wet is able. In the case of dry starting compounds, they should be used in the form of fine powder, and after mixing and, if necessary, provide seals subjected to calcination. However, thorough mixing is preferably subjected to wet the source of the connection.

This is usually mixed with each other starting compound in the aqueous solution and/or suspension. Especially thoroughly mixed in a similar way dry mix get in if you come from sources of items that are exclusively in the dissolved state. The solvent preferably use water. The resulting aqueous mass is preferably dried in the spray dryer at a temperature output component from 100 to 150°C.

Containing molybdenum and vanadium active polymetallic oxide mass primarily of General formula (IV) can be used for partial oxidation of acrolein in acrylic acid, implemented proposed in the invention method, as in powder form and in the form obtained by forming a catalyst with certain geometrical parameters, and the shaping may be effected before or after the annealing. For example, a seal located in a powdered state active mass or appropriate, not subjected is the annealing of the initial mass, carried out, for example, methods tabletting, extrusion or extrusion, can be obtained having the desired geometric shape of the solid catalysts, and seal if necessary, can be accomplished with the addition of auxiliary agents, such as graphite or stearic acid, used to improve slip and/or facilitate molding, and reinforcing means, such as microfibers of glass, asbestos, silicon carbide or potassium titanate. Suitable geometric form of solid catalysts correspond, for example, solid or hollow cylinders having an external diameter and a length constituting from 2 to 10 mm, the wall Thickness of the hollow cylinder in a suitable variant is from 1 to 3 mm Solid catalyst, obviously, can have the shape of balls, the diameter of which may range from 2 to 10 mm

The molding powder of the active mass or appropriate, not subjected to calcination powder of the initial mass, obviously, you can also make its application to molded inert carrier for catalysts. The application of active mass on the molded body of the carrier with the aim of obtaining shell catalysts, as a rule, is carried out in a suitable rotating the tank, for example, described in German patent application DE-A 2909671 or Euro is Yeysk the patent applications EP-A 293859 and EP-A 714700.

Applied to the molded body of powdered media weight it is advisable to put moisture, and after application, drying, for example, hot air. Suitable thickness is deposited on the body of the carrier layer of the powder mass is from 10 to 1000 μm, preferably from 50 to 500 μm and particularly preferably from 150 to 250 microns.

While the material of the carrier may be conventional porous or nonporous aluminum oxide, silicon dioxide, thorium dioxide, zirconium dioxide, silicon carbide or silicates such as magnesium silicate or aluminum silicate. The pH of the media, you can make regular or irregular shape, and are preferred body media regular shape, for example, balls or hollow cylinders with a distinct surface roughness. Suitable are having a rough surface, mainly non-porous spherical body media from steatite diameter from 1 to 10 mm (for example, 8 mm), preferably from 4 to 5 mm are also Suitable body of the carrier in the form of a cylinder of length from 2 to 10 mm and an external diameter of from 4 to 10 mm In the case according to the invention is suitable bodies media are rings, in addition to these settings, they are characterized by thick walls, usually component from 1 to 4 mm, Preferably used according to the invention the number of zobrazenie body media have a length of from 3 to 6 mm, an external diameter of from 4 to 8 mm and wall thickness from 1 to 2 mm According to the invention is suitable bodies of the media first and foremost are also rings with dimensions of 7 mm × 3 mm × 4 mm (external diameter × length × internal diameter). The thickness of the layer of catalytically active oxide mass applied on the surface of the body of the carrier, obviously, should be in accordance with the required thickness of the shell (see European patent application EP-A 714700).

Besides containing molybdenum and vanadium optimal active polymetallic oxide masses intended for partial oxidation of acrolein in acrylic acid proposed in the invention method are active mass General formula (VI):

,

in which

D means Mo12VaZ1bZ2c"Z3dZ4eZ5fZ6gOx",

E. means Z712CuhHi"Cy,

Z1means tungsten, niobium, tantalum, chromium and/or cerium,

Z2means copper, Nickel, cobalt, iron, manganese and/or zinc,

Z3means antimony and/or bismuth,

Z4means lithium, sodium, potassium, rubidium, cesium and/or hydrogen

Z5means magnesium, calcium, strontium and/or barium,

Z6means silicon, aluminum is tions, titanium and/or zirconium,

Z7means molybdenum, tungsten, vanadium, niobium and/or tantalum,

a" means a number from 1 to 8

b" means a number from 0.2 to 5,

with" means a number from 0 to 23

d" denotes a number from 0 to 50,

e" means a number from 0 to 2,

f" means a number from 0 to 5,

g" means a number from 0 to 50,

h" means a number from 4 to 30,

i" denotes a number from 0 to 20,

x", y" means the number determined by the valency and frequency different from the oxygen elements in the General formula (VI), and

p, q mean different from zero numbers whose p/q is from 160:1 to 1:1, which can be received by a formation of a solid finely dispersed polymetallic oxide mass (E):

(initial mass 1) and the subsequent introduction of a formed solid source mass 1 (subject to the necessary quantitative relationships p to q) in aqueous solution, aqueous suspension or fine dry stoichiometric mixture (D):

sources of molybdenum, vanadium, Z1, Z2, Z3, Z4, Z5, Z6(initial mass 2), if necessary, carried out by drying the resulting aqueous mixture and calcining the dry initial mass before or after drying at a temperature of from 250 to 600°C, resulting in a gain catalyst with h the necessary geometrical parameters.

While preferred are polymetallic oxide mass General formula (VI), obtained by introducing the formed solid source mass 1 in the water source mass 2, carried out at a temperature below 70°C. the Preparation of catalysts based on polymetallic oxide mass General formula (VI) are discussed in detail, for example, in European patent application EP-A 668104 and German patent applications DE-A 19736105 and DE-A 19528646.

Forming catalysts based on polymetallic oxide mass General formula (VI) perform similarly to the formation of catalysts on the basis of polymetallic oxide mass General formula (IV).

Other containing molybdenum and vanadium optimal active polymetallic oxide masses, to be used for partial oxidation of acrolein in acrylic acid proposed in the invention method are active mass General formula (VII):

,

in which

And means Mo12VaX1bX2cX3dX4eX5fX6gOx,

In means X17CuhHiOy,

With means X18SbjHkOz,

X1means tungsten, niobium, tantalum, chromium and/or cesium, preferably tungsten, Niobe and/or chromium,

X2means copper, Nickel, cobalt, iron, manganese and/or zinc, preferably copper, Nickel, cobalt and/or iron,

X3means antimony and/or bismuth, preferably antimony,

X4means lithium, sodium, potassium, rubidium, cesium and/or hydrogen, preferably sodium and/or potassium,

X5means magnesium, calcium, strontium and/or barium, preferably calcium, strontium and/or barium,

X6means silicon, aluminum, titanium and/or zirconium, preferably silicon, aluminum and/or titanium,

X7means molybdenum, tungsten, vanadium, niobium and/or tantalum, preferably molybdenum and/or tungsten,

X8means copper, Nickel, zinc, cobalt, iron, cadmium, manganese, magnesium, calcium, strontium and/or barium, preferably copper and/or zinc, especially preferably copper,

a represents a number from 1 to 8, preferably from 2 to 6,

b denotes a number from 0.2 to 5, preferably from 0.5 to 2.5,

by means of a number from 0 to 23, preferably from 0 to 4,

d is a number from 0 to 50, preferably from 0 to 3,

E. means a number from 0 to 2, preferably from 0 to 0.3,

f denotes a number from 0 to 5, preferably from 0 to 2,

g denotes a number from 0 to 50, preferably 0 to 20,

h stands for a number from 0.3 to 2.5, preferably from 0.5 to 2, especially preferably from 0.75 to 1.5,

i is a number from 0 to 2, predpochtitelno from 0 to 1,

j denotes a number from 0.1 to 50, preferably from 0.2 to 20, particularly preferably from 0.2 to 5,

k is a number from 0 to 50, preferably from 0 to 20, particularly preferably from 0 to 12,

x, y, z means the number determined by the valency and frequency different from the oxygen elements in the areas a, b, C,

p, q denote a positive number

r is 0 or a positive number, preferably a positive number and the ratio of p to (q+r) is from 20:1 to 1:20, preferably from 5:1 to 1:14, particularly preferably from 2:1 to 1:8, as at r, which means a positive number, the ratio of q to r is from 20:1 to 1:20, preferably from 4:1 to 1:4, particularly preferably from 2:1 to 1:2 and more preferably 1:1,

moreover, the component [A]pcontained in the active mass of General formula (VII) in the form of three-dimensional regions (phases) And having the chemical composition:

Mo12VaX1bX2cX3dX4eX5fX6gOx,

component [B]qcontained in the product of General formula (VII) in the form of three-dimensional regions (phases), with chemical composition:

X17CuhHiOy,

and the component [C]rcontained in the product of General formula (VII) in the form of three-dimensional regions (phases), with chemical composition:

X1 8SbjHkOz,

moreover, the distribution of areas a, b and if necessary, With each other like distribution, characteristic of a mixture of finely dispersed component And, dispersed component and optionally finely dispersed component, and all variables specified areas should be selected so that the molar content of molybdenum in the total number of all dierent from oxygen elements active multi-element oxide mass General formula (VII) ranged from 20 to 80 mol%, the molar ratio of mo contained in the catalytically active multi-element oxide mass General formula (VII), it contains the vanadium (Mo:V) ranged from 15:1 to 1:1, the corresponding molar ratio of molybdenum to copper (Mo:Cu) ranged from 30:1 to 1:3 and the corresponding molar ratio of molybdenum to the total amount of tungsten and niobium ranged from 80:1 to 1:4.

In accordance with the invention, the preferred active multi-element oxide mass General formula (VII) are active mass, area And which are characterized by the stoichiometric composition of the General formula (VIII):

,

in which

X1means tungsten and/or niobium,

X2mean copper and/or Nickel,

X5mean calcium and/is whether strontium,

X6means silicon and/or aluminum,

a represents a number from 2 to 6,

b denotes a number from 1 to 2,

by means of a number from 1 to 3,

f denotes a number from 0 to 0.75,

g denotes a number from 0 to 10 and

x means the number determined by the valency and frequency different from the oxygen elements and the General formula (VIII).

The term "phase" is used when considering active multielement oxide mass General formula (VII) to denote three-dimensional regions of the chemical composition of which differs from the chemical composition of the surrounding material. These phases do not have inevitable rentgenograficheski find uniformity. Phase And, as a rule, represents the continuous phase in which the dispersed particle phase and, if necessary, phase C.

Finely dispersed phase and, if necessary, the phase preferably consists of particles, the greatest diameter of which, that is passing through their center of gravity of the longest line segment between two on-surface point, up to 300 μm, preferably from 0.1 to 200 μm, particularly preferably from 0.5 to 50 μm and even more preferably from 1 to 30 μm. However, suitable are particles, the greatest diameter of which ranges from 10 to 80 microns, or from 75 to 125 μm.

In principle, phase a, b and if necessary phase, codereading active multielement oxide masses of the General formula (VII), can be amorphous or crystalline.

Thoroughly mixed dry mixture, which is the basis of active multielement oxide mass General formula (VII) and subjected to subsequent heat treatment to transform the active mass can be obtained, for example, methods described in international application WO 02/24327, German patent applications DE-A 4405514, DE-A 4440891, DE-A 19528646, DE-A 19740493, European patent application EP-A 756894, German patent applications DE-A 19815280, DE-A 19815278, European patent application EP-A 774297, German the patent application DE-A 19815281, European patent application EP-A 668104 and German patent application DE-A 19736105.

The basic principle of obtaining thoroughly mixed dry mixtures that form after the heat treatment active multielement oxide mass General formula (VII), consists in the formation of at least one finely dispersed multielement oxide mass In (X17CuhHiOyas the initial mass 1, and optionally one or more finely dispersed multi-element oxide masses (X18SbjHkOzas the initial mass 2, carried out independently of each other or jointly, the subsequent implementation contact (thoroughly mixed) initial mass of 1 and, if necessary, the initial mass 2 with the mixture, the soda is containing in the appropriate stoichiometric ratio of the sources of the elementary components of multi-element oxide mass And

(cited in contact components are necessary according to the General formula (VII) quantitative ratio), and, if necessary, carried out by drying the resulting mixture is thoroughly mixed components.

Intimate contact (complete mixing) of the initial mass 1, and optionally the initial mass 2 with a mixture containing sources of elemental components polymetallic oxide mass (initial mass 3), can be implemented as a dry or wet method. When using the wet method, special attention should be paid only to the formed phases (crystallites) and, if necessary, With not passed into the solution. Such requirement in the case of the water environment is usually performed due to the fact that the pH is not too much different from 7, and the temperature of mixing is not too high. In case of implementation contact (thorough mixing of the components wet method in conclusion usually are drying (e.g. spray drying), leading to the formation of thoroughly mixed dry mixture according to the invention is subject to subsequent heat treatment. In the case of dry mixing is similar to the dry mass is formed automatically. Formed finely dispersed phase and, if necessary, phases, obviously, can be entered also capable of plastic deformation mixture containing sources of elements polymetallic oxide mass And, in accordance with the recommendations contained in the German patent application DE-A 10046928. To realize the intimate contact of the components of the initial mass 1, and optionally the initial mass 2 source elements of the multielement oxide mass (initial mass 3), obviously, you can also use the method described in the German patent application DE-a 19815281.

Heat treatment with the aim of obtaining active mass and shape can be performed similarly active polymetallic oxide mass General formulas (IV)-(VI).

In General, catalysts based on active polymetallic oxide mass General formulas (IV)-(VII) preferably can be obtained in accordance with German patent application DE-A 10325487, respectively, DE-A 10325488.

In the most simple and feasible in the production-technical version of the reaction stage of the conversion of propylene to acrolein (in the system of oxidation reactors used according to the proposed invention method) on the above catalysts suitable for use in stationary layer can be implemented in a tubular reactor with loaded fixed bed of catalyst, as described, for example, ineuropean the patent application EP-A 700714, accordingly the German patent application DE-A 4431949, or international applications WO 03/057653, WO 03/055835, WO 03/059857 and WO 03/076373.

Therefore, in the most simple (single-band) version of the fixed catalyst bed in a standard way loaded into a metal tube of the tubular reactor, around which moves thermostatic environment, which, as a rule, use molten salt. When this molten salt (thermostatic environment) and the reaction gas mixture can be moved relative to each other by a simple co-current or countercurrent. However, the heating and cooling medium (molten salt) can move around the beam pipe along the winding path (if you look at the reactor top), allowing the heating and cooling medium moves with a co-current or counter-current relative to the direction of flow of the reaction gas mixture over the whole cross section of the reactor (when viewed from the top). Thus the volume flow of the heating and cooling medium (coolant) is usually calculated so that due to ekzotermicheskie reactions increase its temperature when moving from the insertion point in the reactor to the point of exit from the reactor ranged from 0 to 10°C., often from 2 to 8°C., often from 3 to 6°C. the temperature of the coolant at the entrance to the tubular reactor generally ranges from 250 to 450°C., often from to 400°C, accordingly, from 300 to 380°C. In these temperature ranges change occurs and the corresponding reaction temperature. As the coolant is primarily suitable thermostatic liquid environment. Especially favorable is the use of molten salts such as potassium nitrate, potassium nitrite, sodium nitrite and/or sodium nitrate, or of low-melting metals such as sodium, mercury and alloys of various metals. However, as the heat can also be used ionic liquids.

In a suitable embodiment, the source of the reaction gas mixture before introduction into the fixed catalyst bed is heated to the required reaction temperature.

In accordance with the proposed invention method is preferably carried out prior to the preparation of the source of the reaction gas mixture, which is then using the appropriate distribution system at the same time introducing at least two parallel operating system reactor oxidation.

Partial oxidation of propylene to acrolein is advisable to be implemented in dual-zone or multi-zone tubular reactor, especially in case of high preset flow rate of propylene through a stationary catalyst bed comprising, for example, ≥130 nl/l·h, ≥140 nl/l·h, ≥nl/l·h or ≥160 nl/l·h, however, as PR is usually ≥600 nl/l·h, frequently ≥350 nl/l·h, although the above reaction can be carried out in one zone of the tubular reactor. The preferred option design dual-zone tubular reactor according to the invention can be used for the aforementioned purpose, is described in German patent application DE-2830765. However, also suitable dual-zone tubular reactor proposed in the German patent application DE-C 2513405, the application of the U.S. patent US-A 3147084, German patent application DE-A 2201528, European patent application EP-A 383224 and German patent application DE-a 2903582. Appropriate technology is also described in European patent application EP-A 1106598.

Thus, in accordance with a simple variation of at least one fixed layer to be used catalyst according to the invention loaded in a standard way in a metal tube of the tubular reactor, around which move mainly two spatially separated from each other thermostatic environment, which, as a rule, are the salt melts. The reaction area is considered the area of the reactor tube surrounded by a corresponding salt melt.

So, for example, molten salt And preferably wraps around the tube that section of the reactor (reaction zone), which corresponds to the degree of oxidative conversion of propylene is (if a single transmission) from 40 to 80 mol%, while the salt melt, preferably wraps around the tube that section of the reactor (reaction zone), which corresponds to a further oxidative conversion of propene (in single-transmission), the degree of which usually reaches at least 93 mol%. (to the reaction zones a and b if necessary, can adjoin additional reaction zone to keep them in individual temperature regimes).

Molten salt can circulate inside the respective temperature zones similar to single-band version. The temperature of the salt melt In the inlet to the reactor is typically greater than the corresponding temperature of the salt melt And the amount of at least 5 to 10°C. the temperature of the molten salt at the entrance can be, in particular, recommended for single-band version temperature range.

In addition, dual-zone technology partial oxidation of propylene to acrolein at an increased flow rate of the propylene feedstock can be implemented, for example, in accordance with German patent application DE-a 10308836, European patent application EP-A 1106598, international application WO 01/36364 or German patent applications DE-a 19927624, DE-A 19948523, DE-A 10313210, DE-A 10313213, DE-AND 19948248.

Proposed in the invention, the method is generally suitable for partially the CSOs oxidation of propylene to acrolein at a flow rate of propylene through a stationary catalyst bed, average ≥70 nl/l·h or ≥70 nl/l·h, ≥90 nl/l·h, ≥110 nl/l·h, ≥130 nl/l·h, ≥140 nl/l·h, ≥160 nl/l·h, ≥180 nl/l·h, ≥240 nl/l·h or ≥300 nl/l·h, which, however, usually limit values ≥600 nl/l·including These data in the General case refer to the volume of the fixed catalyst layer minus if necessary, shared areas of the stationary layer consisting only of inert material (excluding contemplated by this invention other cases).

According to the invention preferably choose the same consumption of propylene of at least two respective parallel operating system reactor oxidation.

For the preparation of at least one fixed catalyst for partial oxidation of propylene to acrolein proposed in the invention method, you can use the molded body of the catalyst containing the active polymetallic oxide mass, or substantially homogeneous mixture of such molded bodies and a molded body containing no active polymetallic oxide mass and having a predominantly inert behavior with respect to the heterogeneously catalyzed partial vapor-phase oxidation (made from an inert material dilution molded body). Materials such inert shaped bodies principle can be any of the substances also suitable for use as materials of the carrier shell catalysts for the synthesis of acrolein from propylene. Such suitable substances can be, for example, porous or non-porous aluminiumoxide, silicon dioxide, thorium dioxide, zirconium dioxide, silicon carbide, silicates such as magnesium silicate or aluminum silicate, or the above-mentioned steatite (for example, product Steatit-220 CeramTec).

Appropriate inert dilution molded body may have any geometrical parameters. That is, they can be, for example, balls, polyhedra, solid cylinders or rings. Preferred are inert dilution molded body, the geometric parameters of which are similar geometrical parameters diluted their molded bodies catalysts for one-step synthesis.

As a rule, favorable, if the active weight used for given partial oxidation of propylene to acrolein, has the same chemical composition throughout the volume of the fixed catalyst layer. Therefore, although used for individual molded bodies of the active mass of the catalyst and may be a mixture of different polymetallic oxides, for example, contains elemental molybdenum and/or tungsten, and at least od the n of elements, selected from the group comprising bismuth, iron, antimony, tin and copper, in this case, all molded bodies stationary catalyst layer preferably use the same mixture.

According to the invention at least two of the considered parallel operating system reactor oxidation preferably consist of reactors loaded with the same catalyst.

In partial oxidation of propylene to acrolein referred to unit of volume of activity within the stationary layer of the catalyst in a flow direction of the source of the reaction gas mixture is usually preferably increases continuously, abruptly or stepwise manner.

While assigned to the unit volume activity can be reduced by a simple method, for example, due to the homogeneous dilution of the base standard way custom molded bodies of catalyst dilution molded bodies. The higher the content of dilution molded bodies, the lower the content of the active mass in a certain volume of stationary catalyst layer, respectively, are active.

Thus, to control the direction of flow of the reaction gas mixture at least once increased activity related to the unit volume of the stationary catalyst layer, you can simple method is m, for example, due to the fact that the filling start with a high content of inert dilution molded bodies in a molded bodies of a catalyst of this type, and then the high content of dilution molded bodies is reduced in the direction of flow either continuously or sharp (e.g., speed) of at least single or multiple cuts. The increase is attributed to the unit volume of activity can be implemented, for example, due to the fact that when stored unchanged geometrical parameters of the molded bodies of shell catalyst and type of active mass increase thickness deposited on the corresponding carrier layer of the active mass, or due to the fact that in a mixture of shell catalysts with the same geometrical parameters, but different mass content of the active mass, increase the proportion of molded bodies of a catalyst with a higher mass content of the active mass. In accordance with another variant is possible also to dilute themselves active mass, which, for example, when cooked in subject to calcination dry mixture of the source compounds injected inert materials with dilution effects, such as highly annealed silicon dioxide. Variation added amount of such dilution of the material provides the appropriate automatic the mechanical changes in the activity of the active mass. The more the number of the added dilution of the material, the lower the activity of the diluted them active mass. A similar effect can be achieved, for example, by varying the ratio contained in the respective mixtures of solid and shell catalysts with identical active masses. The above options, obviously, can also be used in combination.

Partial oxidation of propylene to acrolein according to the invention obviously can be done in a fixed layer consisting of a mixture of catalysts, which contain the active mass of different chemical composition and, consequently, have different activity. Such mixtures can also be diluted with inert molded dilution bodies.

Before containing the active mass plots of the stationary layer of the catalyst used for the partial oxidation of propylene to acrolein proposed in the invention method, and/or in addition to such lots may be bulk layers, consisting only of inert material (for example, dilution of molded bodies). Such bulk layers can be heated to the temperature of the fixed catalyst layer. This inert bulk layers can consist of dilution molded bodies, geometrical parameters to the verge of a similar geometrical parameters of the molded bodies of the catalyst, used to create the above contains the active mass plots. However, dilution molded body is inert bulk layers and molded catalyst body may also have different geometric parameters (e.g., dilution molded body may be spherical, not a circle).

Molded body is used to create a similar inert bulk layers, often have the form of rings with dimensions of 7 mm × 7 mm × 4 mm (external diameter × length × internal diameter) or the form of beads with a diameter from 4 to 5 mm.

In accordance with the proposed invention is a method containing the active mass plot of the stationary layer of catalyst for partial oxidation of propylene to acrolein is often structured in a flow direction of the reaction gas mixture as follows (according to the invention is preferably applies to all of the at least two proposed in the invention in parallel operating systems reactor oxidation is performed in the same way).

In the initial (first) zone containing the active mass plot of the stationary catalyst layer, the length of which is from 10 to 60%, preferably from 10 to 50%, particularly preferably from 20 to 40% and even more preferably from 25 to 35% of the total length of this section (that is, for example, from 0.70 to 50 m , preferably from 0.90 to 1.20 m), there are one or two sequentially loaded homogeneous mixture (with decreasing degree of dilution), consisting of molded bodies of catalyst and dilution molded bodies (bodies of both types preferably have basically the same geometrical parameters), and the mass content of the dilution molded bodies molded body of catalyst and dilution molded body, as a rule, only slightly differ from each other in density) is usually from 5 to 40 wt%, preferably from 10 to 40 wt%, or from 20 to 40 wt%, and particularly preferably from 25 to 35% of the mass. For the first area, second area, often preferably continued until the end containing the active mass plot of the stationary catalyst layer (i.e. the length of the second zone is, for example, from 2.00 to 3.00 m, preferably from 2.50 to 3.00 m), which is either slightly diluted (like the first zone) bulk layer molded bodies of a catalyst, or (in a particularly preferred variant) undiluted bulk layer molded bodies of a catalyst similar to that used in the first zone.

The above primarily relates to the use of stationary catalyst layer containing as molded bodies annular one-piece or bolocera catalysts (especially those listed in this application as preferred). In accordance with the proposed invention is a method for the above-described structure, preferably using a ring-shaped molded body of the catalyst, respectively, the media, and the annular dilution molded body, which generally have dimensions of 5 mm × 3 mm × 2 mm (external diameter × length × internal diameter).

The above applies also to the case when instead of the inert dilution molded bodies use molded body shell of the catalyst, the content of the active mass which is lower than the content at the end of the stationary layer molded body shell of the catalyst in the amount of from 2 to 15% of the mass.

Consisting only of inert material of the bulk layer, the length of which in a suitable embodiment, ranges from 5% to 20% of the total length of the fixed catalyst layer, as a rule, is located in front of the stationary layer in the flow direction of the reaction gas mixture). The layer of inert material is usually used as zone heating the reaction gas mixture.

Contact tube of the tubular reactor, designed to implement stage partial oxidation of propylene to acrolein, usually made of ferrite steel, and the thickness of their walls in type is cnom case is from 1 to 3 mm. The internal diameter of the tubes, generally ranges from 20 to 30 mm, frequently from 21 to 26 mm Suitable in industrial-technical terms the number placed in a tubular reactor contact tubes is at least 5000, preferably at least 10000. The number of contact tubes in a tubular reactor often ranges from 15000 to 30000. Tubular reactors with a number of contact tubes in excess of 40000 to implement the above reaction stages are used only in exceptional cases. The contact tube is usually distributed inside the tubular reactor uniformly, and the distribution is advisable to choose a so that a so-called step contact tubes (the distance between the Central internal axes of adjacent pin tubes) ranged from 35 to 45 mm (see, for example, European patent application EP-468290).

Phase transformations of acrolein in acrylic acid by known catalysts suitable for the implementation of this reaction in the stationary layer, according to the most simple and the production is technically feasible option can also be carried out in a tubular reactor with a fixed bed of catalyst, as described, for example, in European patent application EP-A 700893, respectively, of German patent application DE-A 4431949 or in international applications WO 03/057653, WO 03/055835, W 03/059857 or WO 03/076373.

Thus, in accordance with the most simple (single-band) option a stationary catalyst bed loaded in the standard manner in a metal tube of the tubular reactor, around which moves the heating and cooling medium, which typically is a molten salt. When this molten salt (thermostatic environment) and the reaction gas mixture can be moved relative to each other by a simple co-current or countercurrent. However, the heating and cooling medium (molten salt) can move around the beam pipe along the winding path (if you look at the reactor top), so that the movement of thermostatic environment with a co-current or counter-current relative to the direction of flow of the reaction gas mixture occurs over the whole cross section of the reactor (when viewed from the top). Thus the volume flow of the heating and cooling medium (coolant) is usually calculated so that due to ekzotermicheskie reactions increase its temperature when moving from the insertion point in the reactor to the point of exit from the reactor ranged from 0 to 10°C., often from 2 to 8°C., often from 3 to 6°C. the temperature of the coolant at the entrance to the tubular reactor (in the present description it corresponds to the temperature of the fixed catalyst layer), generally ranges from 220 to 350°C., often from 245 to 285°C, with the responsibly from 245 to 265°C. As the coolant is primarily suitable thermostatic liquid environment. Especially favorable is the use of molten salts such as potassium nitrate, potassium nitrite, sodium nitrite and/or sodium nitrate, or of low-melting metals such as sodium, mercury and alloys of various metals. However, as the heat can also be used ionic liquids.

In a suitable embodiment, the source of the reaction gas mixture before introduction into the fixed catalyst bed is heated to the required reaction temperature.

Partial oxidation of acrolein in acrylic acid proposed in the invention method, it is advisable to realize in dual-zone or multi-zone tubular reactor, especially in case of high preset flow rate of acrolein through a stationary catalyst bed comprising, for example, ≥130 nl/l·h or ≥140 nl/l·h, but, as a rule, ≤350 nl/l·h or ≤600 nl/l·h, although the above reaction can be carried out in one zone of the tubular reactor. The preferred embodiment dual-zone tubular reactor according to the invention can be used for the aforementioned purpose, is described in German patent application DE-C 2830765. However, also suitable dual-zone tubular reactor proposed in the German patent application DE-2513405, the application of the U.S. patent US-A 147084, German patent application DE-A 2201528, European patent application EP-A 383224 and German patent application DE-A 2903582.

Thus, in accordance with a simple variation of at least one fixed layer to be used according to the invention the catalyst of the standard image is loaded into a metal tube of the tubular reactor, around which move mainly two spatially separated from each other thermostatic environment, which, as a rule, use salt melts. The reaction zone is the area of the reactor tube surrounded by a corresponding salt melt.

For example, a salt melt, preferably wraps around the tube that section of the reactor (reaction zone), which corresponds to the degree of oxidative transformation of acrolein (if a single transmission) from 55 to 85 mol%, while the molten salt D preferably wraps around the tube that section of the reactor (reaction zone D), which corresponds to a further oxidative transformation of acrolein (if a single transmission), the degree of which usually reaches at least 90 mol%. (to the reaction zones C and D, if necessary, can adjoin additional reaction zone to keep them in individual temperature regimes).

Molten salt is the principle can circulate inside the respective temperature zones similarly to the single-band version. The temperature of the salt melt D at the entrance to the reactor is typically greater than the corresponding temperature of the salt melt in the amount of at least 5 to 10°C. the temperature of the molten salt at the entrance can be, in particular, recommended for single-band version temperature range.

In addition, dual-zone technology partial oxidation of acrolein in acrylic acid at an elevated consumption of the source acrolein can be implemented, for example, in accordance with German patent application DE-A 19948523, European patent application EP-A 1106598 or German patent application DE-A 19948248.

Therefore, proposed in the invention method is suitable for the implementation of the partial oxidation of acrolein in acrylic acid at the flow rate through a stationary catalyst bed comprising ≤70 nl/l·h or ≥70 nl/l·h, ≥90 nl/l·h, ≥110 nl/l·h, ≥130 nl/l·h, ≥180 nl/l·h, ≥240 nl/l·h, ≥300 nl/l·h, but usually limited to values ≤600 nl/l·h These data in General apply to the volume of the fixed catalyst layer minus if necessary, shared areas, consisting only of inert material.

For the preparation of at least one fixed catalyst layer, intended for realization of the partial oxidation of acrolein in acrylic acid is proposed in the invention method, you can use the molded body of the catalyst containing the active polymetallic oxide mass, or substantially homogeneous mixtures of shaped bodies of a catalyst containing active polymetallic oxide mass, and a molded body containing no active polymetallic oxide mass, with a predominantly inert behavior with respect to the heterogeneously catalyzed partial vapor-phase oxidation (made from an inert material dilution molded body). Materials such inert shaped bodies, in principle, can be any of the substances suitable for use as materials of the carrier shell catalysts for the conversion of acrolein in acrylic acid. Such suitable substances can be, for example, porous or non-porous aluminiumoxide, silicon dioxide, thorium dioxide, zirconium dioxide, silicon carbide, silicates such as magnesium silicate or aluminum silicate, or the above-mentioned steatite (for example, product Steatit-220 CeramTec).

Appropriate inert dilution molded body may have any geometrical parameters. That is, they can be, for example, balls, polyhedra, solid cylinders or rings. According to the invention are preferred inert of resbala the existing molded body, geometric parameters of which are similar geometrical parameters diluted their molded bodies catalysts.

As a rule, favorable, if the active weight used for given partial oxidation acrolein in acrylic acid, has the same chemical composition throughout the volume of the fixed catalyst layer. Therefore, although used for individual molded bodies of the active mass of the catalyst and may be a mixture of different polymetallic oxides, for example, contains elemental molybdenum and/or tungsten, in this case, all molded bodies stationary catalyst layer preferably use the same mixture.

In partial oxidation of acrolein in acrylic acid referred to unit of volume of activity within the stationary layer of the catalyst in a flow direction of the source of the reaction gas mixture is usually preferably continuously, abruptly or step increases.

While assigned to the unit volume activity can be reduced by a simple method, for example, due to the homogeneous dilution of the base standard way custom molded bodies of catalyst dilution molded bodies. The higher the content of dilution molded bodies, the lower the content of the active mass in the definition is nnom volume of stationary catalyst layer, according to its activity.

Thus, when implemented according to the invention the partial oxidation of acrolein in acrylic acid to control at least one-time increase in the activity referred to unit of volume of the fixed catalyst layer occurring in the direction of flow of the reaction gas mixture, can be a simple method, for example, due to the fact that the filling start with a high content of inert dilution molded bodies in a molded bodies of a catalyst of this type, and then the high content of dilution molded bodies is reduced in the direction of flow either continuously or sharp (e.g., speed) of at least single or multiple cuts. The increase is attributed to the unit volume of activity can be implemented, for example, due to the fact that when stored unchanged geometrical parameters of the molded bodies of shell catalyst and type of active mass increase thickness deposited on the corresponding carrier layer of the active mass, or due to the fact that in a mixture of shell catalysts with the same geometrical parameters, but different mass content of the active mass, increase the proportion of molded bodies of a catalyst with a higher mass content of the active mass. In accordance with another option is also to dilute themselves active mass, why, for example, when cooked in subject to calcination dry mixture of the source compounds injected inert materials with dilution effects, such as highly annealed silicon dioxide. Variation added amount of such dilution of the material provides the corresponding automatic change of activity of the active mass. The more the number of the added dilution of the material, the lower the activity of the diluted them active mass. A similar effect can be achieved, for example, by varying the ratio between solid and shell catalysts with identical active masses in the respective mixtures. The above options, obviously, can also be used in combination.

Partial oxidation of acrolein in acrylic acid according to the invention obviously can be done in a fixed layer consisting of a mixture of catalysts, which contain the active mass of different chemical composition and, consequently, have different activity. Such mixtures can also be diluted with inert molded dilution bodies.

Before containing the active mass plots stationary catalyst layer and/or in addition to such lots may be bulk layers, consisting only of an inert material (e.g. the R, only dilution of molded bodies). Such bulk layers can be heated to the temperature of the fixed catalyst layer.

This inert bulk layers can consist of dilution molded bodies, geometrical parameters are similar geometrical parameters molded bodies of catalyst used to create the above contains the active mass plots. However, dilution molded body is inert bulk layers and molded catalyst body may also have different geometric parameters (e.g., dilution molded body may be spherical, not a circle).

Molded body is used to create a similar inert bulk layers, often have the form of rings with dimensions of 7 mm × 7 mm × 4 mm (external diameter × length × internal diameter) or the form of beads with a diameter from 4 to 5 mm.

In accordance with the proposed invention is a method containing the active mass plot of the stationary layer of catalyst for partial oxidation of acrolein in acrylic acid is often structured in a flow direction of the reaction gas mixture as follows (according to the invention is preferably applies to all of the at least two proposed in the invention in parallel operating systems react the s oxidation is performed in the same way).

In the initial (first) zone containing the active mass plot of the stationary catalyst layer, the length of which is from 10 to 50%, preferably from 20 to 40%, particularly preferably from 25 to 35% and even more preferably from 25 to 35% of the total length of this section (that is, for example, from 0.70 to 1.50 m, preferably from 0.90 to 1.20 m), there are one or two sequentially loaded homogeneous mixture (with decreasing degree of dilution), consisting of molded bodies of catalyst and dilution molded bodies (body both type preferably have basically the same geometrical parameters), and the mass content of the dilution molded bodies molded body of catalyst and dilution molded body, as a rule, only slightly differ from each other in density) is usually from 10 to 50 wt. -%, preferably from 20 to 45% of the mass. and particularly preferably from 25 to 35% of the mass. For the first area, second area, often preferably continued until the end containing the active mass plot of the stationary catalyst layer (i.e. the length of the second zone is, for example, from 2.00 to 3.00 m, preferably from 2.50 to 3.00 m), which is either slightly diluted (like the first area, respectively, the first two zones) bulk layer molded bodies catalysis is ora, or, even more preferably undiluted bulk layer molded bodies of a catalyst similar to that used in the first zone, respectively in the first two zones.

The above primarily relates to the use of stationary catalyst layer containing as molded bodies annular or spherical shell catalysts (especially those that are in accordance with the present application are preferred for partial oxidation of acrolein in acrylic acid). In accordance with the proposed invention by way of a partial oxidation acrolein in acrylic acid to the above-described structure, preferably using a ring-shaped molded body of the catalyst, respectively, the media, and the annular dilution molded body, which generally have dimensions of 7 mm × 3 mm × 4 mm (external diameter × length × internal diameter).

The above applies also to the case when instead of the inert dilution molded bodies use molded body shell of the catalyst, the content of the active mass which is lower than the content at the end of the stationary layer molded body shell of the catalyst in the amount of from 2 to 15% of the mass.

Consisting only of inert material of the bulk layer, the length is and which is suitable variant ranges from 5% to 20% of the total length used for the partial oxidation of acrolein stationary layer of catalyst, as a rule, is located in front of the stationary layer in the flow direction of the reaction gas mixture). The layer of inert material is usually used as zone heating the reaction gas mixture.

Contact tube of the tubular reactor used at the stage carried out according to the invention the partial oxidation of acrolein, usually made of ferrite steel, and the thickness of their walls in the typical case is from 1 to 3 mm Inner diameter tubes, typically ranges from 20 to 30 mm, frequently from 21 to 26 mm Suitable in industrial-technical terms the number of contact tubes, placed in a tubular reactor is at least 5000, preferably at least 10000. The number of contact tubes in a tubular reactor often ranges from 15000 to 30000. Tubular reactors with a number of contact tubes in excess of 40000 to implement the above reaction stages are used only in exceptional cases. The contact tube is usually distributed inside the tubular reactor uniformly, and the distribution is advisable to choose a so that a so-called step contact tubes (the distance between the Central internal axes of adjacent pin tubes) ranged from 35 to 45 mm (see, for example, European patent application EP-468290).

As described above, in the accordance with the proposed invention by way of a partial oxidation as propylene, and acrolein can be done in one zone or two-zone tubular reactor. However, in the case of a sequential implementation of both reaction stages it is also possible, in accordance with which in one zone of the tubular reactor implement only the first reaction stage, while the second reaction stage is carried out in a two-zone tubular reactor (or Vice versa). Obtained in the first reaction stage, the mixture of gases (preferably by mixing the gases formed in parallel operating systems reactor oxidation) after optionally carried out by adding an inert gas, molecular oxygen or inert gas and molecular oxygen, and after, if necessary, provide direct and/or indirect intercooler sent directly to the second reaction stage.

However, tubular reactors, intended for the implementation of the first and second reaction stages may be located intermediate the refrigerator, which may optionally contain inert bulk layers.

Stationary layer of catalyst for partial oxidation of propylene and the stationary layer of catalyst for partial oxidation of acrolein designed for carrying out the invention method LW is studiinogo partial oxidation of propylene to acrylic acid, obviously, can be located in a spatial sequence within a single tubular reactor with a large number of contact tubes, also including, for example, two or more temperature zones, for example, inside the reactors described in the international application WO 03/059857 and European patent applications EP-A 911313 and EP-A 990636. In this case we are talking about ignoreaction two-stage method. With one or two temperature zones are, as a rule, to one of the stationary layer of catalyst. Between the two fixed layers of catalysts may be additional inert bulk layer, which optionally corresponds to the third temperature area with a separately installable in her temperature. When this contact tube can pass through the inert material layer or be interrupted.

The inert gas used for diluting the source gas mixture phase partial oxidation of propylene to acrolein (the source of the reaction gas mixture 1) regardless of the flow rate of propylene through a stationary catalyst bed (and regardless of whether at the stage of synthesis of acrolein reaction stage partial oxidation of acrolein in acrylic acid) may contain, for example, ≥20% vol., ≥30% vol., ≥40% vol., ≥50% vol., ≥60% vol., ≥70% vol., ≥80% vol., ≥90% of the B. or ≥95%. molecular nitrogen.

This inert dilution gas may be a mixture containing, for example, from 2 to 35 wt%, respectively 20% of the mass. H2O, and from 65 to 98%. of nitrogen.

However, when the flow rate of propylene through a stationary catalyst bed at a stage of partial oxidation to acrolein in excess of 250 nl/l·h, shared inert diluting gases that are recommended for implementation proposed in the invention method are propane, ethane, methane, butane, pentane, carbon dioxide, carbon monoxide, water vapor and/or inert gases. These gases, obviously, can be used in conjunction with propylene and a small flow through a stationary catalyst bed to prevent the occurrence of so-called hot spot.

Working pressure if carried out according to the invention a vapor-phase partial oxidation of propylene to acrolein (especially in the initial period of operation of a stationary catalyst layer) may be lower than normal pressure (for example up to 0.5 bar) or may be higher than normal pressure. In typical cases, the working pressure at the vapor-phase partial oxidation of propylene is from 1 to 5 bar, frequently from 1 to 3 bar.

The reaction pressure when implemented according to the invention headspace is actionem oxidation of propylene to acrolein usually does not exceed 100 bar. Carried out according to the invention the partial oxidation of propylene in the General case, obviously, can be implemented in conjunction with the extension of the service life of the catalyst bed, featured in the European patent applications EP-A 990636, EP-A 1106598, EP-A 614872, German patent applications DE-a 1035822, DE-A 10232748, DE-A 10351269 and DE-A 10 2004025445. Thanks to this combination the service life of catalyst layer can be several years.

The molar ratio of molecular oxygen to propylene in intended for partial oxidation of propylene to acrolein source of the reaction gas mixture 1, the noise in accordance with the proposed invention is a method through the appropriate fixed catalyst bed is typically ≥1:1 (mostly regardless, carry out or not carry out the next stage of partial oxidation of acrolein in acrylic acid). The specified relationship is usually ≤3:1. The molar ratio of molecular oxygen to propylene in the specified source gas mixture is often preferably corresponds to the interval from 1:1 to 2:1, respectively, from 1.4:1 to 2:1. The method of partial oxidation of propylene to acrolein are often implemented when the volume ratio (IO) propylene:oxygen:inert gases (including water vapor) in the original reaction gas mixture 1 of 1:(1-3):(3-3), preferably 1:(1,5-2,3):(10-15).

In this case, the content of propylene in the original reaction gas mixture 1 may be, for example, from 4 to 20% vol., often from 5% to 7% vol. up to 15% vol., accordingly, from 6 or 8% vol. up to 12% vol., or from 5 to 8% vol. (respectively in terms of total volume).

The source of the reaction gas mixture 1 (regardless of the expense, but also from perform and do not perform the subsequent stage partial oxidation of acrolein in acrylic acid) may have the following typical composition:

from 6 to 6.5%. propylene,

from 3 to 3.5%. water,

from 0.3 to 0.5% vol. carbon monoxide,

from 0.8 to 1.2%. carbon dioxide

from 0.01 to 0.04%. acrolein,

between 10.4 to 10.7%. molecular oxygen and

molecular nitrogen (up to 100%),

or

5.4% ABV. propylene,

10,5% vol. oxygen

1,2% vol. COx,

80,5% about. nitrogen and

2,4% about. water.

The source of the reaction gas mixture 1 implemented according to the invention the partial oxidation of propylene to acrolein may have the following composition:

from 6 to 15% vol. propylene,

from 4 to 30% vol. (often 6 to 15% vol.) water,

≥0 to 10% vol. (preferably ≥0 to 5% vol.) components different from propylene, water, oxygen, and nitrogen,

molecular oxygen in an amount such that the molar ratio to molecular propylene is left from 1.5:1 to 2.5:1, and molecular nitrogen (up to total 100% by vol.).

Another source of reaction gas mixture 1 implemented according to the invention the partial oxidation of propylene to acrolein may have the following composition:

6,0% about. propylene,

60% vol. air and

34% about. water.

According to other variants of the invention, the composition of the starting reaction gas mixture 1 for the reaction stage partial oxidation of propylene to acrolein may correspond to the following examples in European patent applications: example 1 (EP-A 990636), example 2 (EP-A 990636), example 3 (EP-A 1106598), example 26 (EP-A 1106598) or example 53 (EP-A 1106598).

Other source of reaction gas mixture 1, which are suitable according to the invention for the implementation of the reaction stage partial oxidation of propylene to acrolein, can have the following structure:

from 7 to 11% vol. propylene,

from 6 to 12% vol. water,

≥0 to 5% vol. components different from propylene, water, oxygen, and nitrogen,

molecular oxygen in an amount such that the molar ratio to molecular propylene ranged from 1.4:1 to 2.2:1, and molecular nitrogen (up to total 100% by vol.).

In the original reaction gas mixture 1 as propylene primarily use propylene polymer grade and chemically pure propylene, for example, in accordance with the German the second patent application DE-a 10232748. In accordance with a preferred embodiment of the invention, the propylene is subjected to a heterogeneously catalyzed vapor-phase partial oxidation with molecular oxygen to acrolein and/or acrylic acid (respectively, the ammoxidation to Acrylonitrile), carried out in at least two parallel operating systems reactor oxidation, you can also use propylene produced heterogeneously catalyzed and/or oxidative dehydrogenation of propane, for example, according to the German patent application DE-A 10245585, international application WO 03/076370, German patent applications DE-A 10316039, DE-A 3313573, U.S. patent US 3161670 and international applications WO 01/96270 WO 01/96271, WO 03/011804. In the preferred embodiment, is subject to oxidation contains propylene propane.

While one reactor dehydrogenation of propane used for feeding propylene, preferably at least two proposed invention in parallel operating system reactor oxidation of propylene.

In this case, the source of the reaction gas mixture 1 preferably has the following composition:

from 7 to 15% vol. molecular oxygen,

from 5 to 10% about. propylene,

10, respectively, 15% vol., up to 40%. propane,

from 25 to 60%. nitrogen,

from 1 to 5% vol. carbon monoxide, carbon dioxide and water in total) and

from 0 to 5% vol. other components,

it does not take into account, if necessary, present the ammonia.

It should be noted that regardless of whether at the stage of conversion of propylene to acrolein reaction phase partial oxidation of acrolein in the acrylic acid portion of the source gas mixture intended for the conversion of propylene to acrolein, may be a so-called recycled gas. As noted above, under the recirculated gas mean gas which remains after separation of the target product (acrolein and/or acrylic acid) obtained in the corresponding system of the reactor gas, which is implemented according to the invention successively attached to the allocation system, and that a maximum of inert dilution gas, usually partially returned to the reaction stage partial oxidation of propylene and/or, if necessary, carry out the subsequent partial oxidation of acrolein in acrylic acid.

As the source of oxygen is usually used air.

The flow of the original reaction gas mixture 1, passed through a stationary catalyst bed (including bulk layer consisting only of inert material), when carried out according to the invention the receiving acrolein and/or acrylic acid from propylene in a typical case the e is primarily from 1000 to 10000 nl/l·h, most often from 1000 to 5000 nl/l·h, frequently from 1500 to 4000 nl/l·h

If after partial oxidation of propylene to acrolein implement phase partial oxidation of acrolein, the gas mixture obtained in stage partial oxidation of propylene, direct to the stage of oxidation of acrolein after optionally performed intermediate cooling. According to the invention is preferred in this case is pre-mixing at least two flows of gas mixtures obtained by partial oxidation of propylene to acrolein. The oxygen required for the implementation phase partial oxidation of acrolein may already be in excess entered in the source of the reaction gas mixture 1-stage partial oxidation of propylene, and therefore, can be a component formed at this stage, the mixture of gases. In such case, if necessary, subjected to intermediate cooling of the gas mixture obtained in stage partial oxidation of propylene, can serve as the source gas mixture is directly used to implement phase partial oxidation of acrolein. However, some of the oxygen or all the oxygen required for the implementation phase partial oxidation of acrolein in the acrylic acid may also be added to the gas mixture obtained in stage oxidation of propylene, re the intake on the reaction stage oxidation acrolein, for example, in the form of air. The added air can simultaneously perform the function of direct cooling of the source gas mixture intended for processing at the stage of partial oxidation of acrolein.

Given the above, the inert gas contained in the source gas mixture for phase partial oxidation of acrolein (the source of the reaction gas mixture 2), regardless preceded whether this reaction stage stage oxidation of propylene may contain, for example, ≥20% vol., ≥30% vol., ≥40% vol., ≥50% vol., ≥ 60% vol., ≥70% vol., ≥80% vol., ≥90%. or ≥95%. molecular nitrogen.

However, the inert dilution gas in the gas mixture is directed to the stage partial oxidation of acrolein often contains from 5 to 25 wt. -%, accordingly, 20% of the mass. water (she can be formed, for example, in the previous phase oxidation of propylene and/or may be optionally added) and from 70 to 90%. of nitrogen.

At a flow rate of acrolein through a stationary catalyst bed partial oxidation of acrolein in acrylic acid in excess of 250 nl/l·h, for carrying out the invention method, it is recommended to use an inert diluting gases such as propane, ethane, methane, butane, pentane, carbon dioxide, water vapor and/or inert gases. However, these gases are, obviously, can jointly use the ü also with low consumption acrolein through the catalyst bed.

Working pressure if carried out according to the invention a vapor-phase partial oxidation of acrolein in acrylic acid (especially at the beginning of operation of a stationary catalyst layer) may be lower than normal pressure (for example up to 0.5 bar) or may correspond to the normal pressure. In typical cases, the working pressure at the vapor-phase partial oxidation of acrolein is from 1 to 5 bar, frequently from 1 to 3 bar.

The reaction pressure when implemented according to the invention the partial oxidation of acrolein usually does not exceed 100 bar. Proposed in the invention method in the General case, obviously, can also be combined with the technology of prolongation of service life of the catalyst bed, featured in the European patent applications EP-A 990636, EP-A 1106598, EP-A 614872 and German patent applications DE-A 10350822, DE-A 10232748, DE-A 10351269 and DE-A 10 2004025445. Thanks to this combination the service life of fixed catalyst layer can be several years.

The molar ratio of oxygen to acrolein in the source gas mixture intended for the reaction stage partial oxidation of acrolein in acrylic acid, implemented proposed in the invention method on the appropriate fixed catalyst bed (whether preceded or not preceded by her reaction is th stage partial oxidation of propylene), is usually ≥1:1. The ratio of these components is typically ≤3. The molar ratio of oxygen to acrolein specified in the source gas mixture according to the invention is often in the range of from 1:1 to 2:1, respectively, from 1:1 to 1.5:1. Proposed in the invention method is often carried out using the source of the reaction gas mixture 2 (initial gas mixture to the reaction stage partial oxidation of acrolein) with a volume ratio of acrolein:oxygen:steam:inert gas (IO)of 1:(1-3):(0-20):(3-30), preferably 1:(1-3):(0.5 to 10):(7-20).

The content of acrolein in the source gas mixture intended for the stage partial oxidation of acrolein, (whether carried out or not carried out before this stage partial oxidation of propylene) may be, for example, 3 or 6% vol. up to 15% vol., often 4 or 6% vol. up to 10% vol., accordingly, from 5 to 8% vol. (in terms of the corresponding total volume). The flow rate of the source gas mixture (the source of the reaction gas mixture 2) through a stationary catalyst bed (excluding bulk layer consisting only of inert material) in accordance with the projects according to the invention the conversion of acrolein in the acrylic acid in the typical case, similarly to the reaction stage of the conversion of propylene to acrolein is from 1000 to 10000 nl·h, most often from 1000 to 5000 nl/l·h, frequently from 1500 to 4000 nl/l·h

When implemented according to the invention the partial oxidation of propylene to acrolein stationary layers of fresh catalyst usually operate so that after the establishment of the permanent composition of the starting reaction gas mixture 1 and its constant flow through the stationary layers of catalyst for partial oxidation of propylene established a temperature of these layers (respectively, the inlet temperature of the heating and cooling medium in the temperature zone of the tubular reactor), in which the degree of conversion of propylene (UPro), achieved as the result of a single pass of the reaction gas mixture 1 through a stationary catalyst layers was at least 93 mol%. By using more efficient catalysts, the degree of conversion of propylene (UPro) can be achieved ≥94 mol%, ≥95 mol%, ≥96 mol%. or ≥97% mol., and often even higher values.

As you proceed heterogeneously catalyzed partial oxidation of propylene to acrolein observe preferential constancy of the composition of the starting reaction gas mixture 1 and its flow through the respective fixed layers of the catalyst (the flow of the original reaction gas mixture 1 if necessary, bring in line with fluctuations Ryno is tion of demand). Reduced activity of the fixed catalyst which occurs in similar production conditions, usually retort, first of all, from time to time increasing the temperature (the temperature of the inlet of the heating and cooling medium in the temperature zone of the tubular reactor; however, the rate of flow of the heating and cooling medium is usually also remains mostly constant), which allows to maintain the degree of conversion of propylene achieved in a single transmission source of the reaction gas mixture, at a given level (i.e. UProis ≥93% mol., ≥94 mol%, ≥95 mol%, ≥96 mol%. or ≥97% mol.).

In addition, according to the invention, it is preferable to such technology vapor-phase partial oxidation of propylene to acrolein, in accordance with which the process from time to time interrupted and the temperature of the stationary layer of the catalyst component of from 250 to 550°C, and through him, miss specified in the German patent application DE-A 10351269 gas mixture G consisting of molecular oxygen, inert gas and optionally steam. Then continue the process of partial oxidation of propylene while maintaining its conditions mostly constant (the restoration of the former consumption of propylene through a stationary catalyst layers provide a preference for the equipment slowly) and set up such a temperature of the fixed catalyst layers, when the degree of conversion of propylene reaches the preset value. At the same degree of conversion of propylene appropriate temperature, usually slightly below the temperature, which had a fixed catalyst bed until the termination of the partial oxidation process with the aim of passing the gas mixture G. Partial oxidation of propylene continue at this temperature stationary catalyst and pre-emptive compliance with the constancy of the other reaction conditions, and what is happening at a time of reduced activity of the fixed catalyst in accordance with a viable option again oppose, from time to time by raising the temperature of the fixed catalyst. According to the invention for, for example, subsequent calendar year, it is advisable at least once again to interrupt the process of partial oxidation, in order to pass through a stationary layers of catalyst gas mixture G. then continue partial oxidation, as described above, and so on. If attainable selectivity of the formation of the target product ceases to meet the applicable requirements, for example, in one of the at least two corresponding systems of reactors oxidation carry out the above replacement part or total to the icesta catalyst, then continue the process according to the invention.

Accordingly, when the implementation proposed in the invention of the method of stationary layers of fresh catalyst for partial oxidation of acrolein in acrylic acid usually operate so that after the establishment of the permanent mode of this reaction stage and the permanent composition of the starting reaction gas mixture 2 and its flow through a stationary catalyst layers established a temperature of these layers (respectively, the inlet temperature of the heating and cooling medium in the temperature zone of the tubular reactor), in which the degree of conversion of acrolein (UAcr), achieved as the result of a single pass of the reaction gas mixture 2 through a stationary catalyst layers was at least 90 mol%. By using more efficient catalysts, the degree of transformation of acrolein (UAcr) can reach ≥92% mol., ≥94 mol%, ≥96 mol%. or ≥98 mol%, and often even ≥99 mol%. and higher values.

As you proceed heterogeneously catalyzed partial oxidation of acrolein in acrylic acid observe preferential constancy of the composition of the starting reaction gas mixture 2 and its flow through the respective fixed layers of the catalyst (consumption, the source of the reaction gas mixture 2 if necessary the value of lead in accordance with fluctuations in market demand). Reduced activity of the fixed catalyst which occurs in similar production conditions, usually retort, first of all, from time to time increasing the temperature (the temperature of the inlet of the heating and cooling medium in the temperature zone of the tubular reactor; however, the rate of flow of the heating and cooling medium is usually also remains mostly constant), which allows to maintain the degree of transformation of acrolein in a single transmission source of the reaction gas mixture 2 at a given level (i.e. UAcris ≥90 mol%, ≥92% mol., ≥94 mol%, ≥96 mol%, ≥98 mol%. or ≥99% mol.).

In addition, it is preferable for this embodiment of the vapor-phase partial oxidation of acrolein in acrylic acid, according to which, for example, before taking the temperature increase of the fixed catalyst on the magnitude, long-term component of ≥10°C or ≥8°C (relative to the temperature established before this stationary layer), a vapor-phase partial oxidation of at least momentarily interrupted and the temperature of the stationary layer of the catalyst component of from 200 to 450°C, through a stationary catalyst bed partial oxidation of acrolein in acrylic acid is passed gas mixture G (noise at the two-stage partial OK the lenii of propylene to acrylic acid via stationary layers of catalyst for partial oxidation of propylene to acrolein). Then continue the process of partial oxidation of acrolein while maintaining its conditions mostly constant (the restoration of the former consumption acrolein through the corresponding stationary catalyst bed preferably carried out slowly, for example in accordance with German patent application DE-A 10337788) and set up such a temperature of the fixed catalyst layers, in which the degree of conversion of acrolein reaches the preset value. At the same degree of transformation of acrolein appropriate temperature, usually slightly below the temperature, which had a fixed catalyst bed until the termination of the partial oxidation process, undertaken with the purpose of passing the gas mixture G. Partial oxidation of propylene continue at this temperature stationary catalyst layer and the preferential adherence of constancy other reaction conditions, and what is happening at a time of reduced activity of the fixed catalyst in accordance with a viable option again oppose, from time to time by raising the temperature of the fixed catalyst. For example, before taking the temperature increase of the fixed catalyst on the magnitude, long-term component of ≥10°C or ≥8°C, again interrupted by the partial oxidation process is of crolina order to pass through a stationary catalyst bed partial oxidation of acrolein in the acrylic acid gas mixture G (optionally passed through a stationary catalyst bed reaction stage oxidation of propylene). Then again carry out the partial oxidation of acrolein, as described above, and so on. If attainable selectivity of the formation of the target product ceases to meet the applicable requirements, for example, in one of the at least two corresponding systems of reactors oxidation carry out the above replacement of a part or the total quantity of catalyst, and then continue the process according to the invention.

In the General case of a heterogeneously catalyzed partial oxidation of acrolein in acrylic acid should be implemented in such a way that the flow of this gas remained from 1.5 to 3.5%. the oxygen. According to the invention, acrylic acid is preferably separated from the mixture flows produced gas. Similar allocation of acrylic acid and, as a rule, accompanying the formation of the recirculated gas can be realized, for example, on-line selection of the target product, as proposed in international application WO 97/48669, the application of the U.S. patent US-A 2004/0242826, international application WO 01/96271 and U.S. patent US 6410785.

Since the efficiency of the separation by rectification columns with the increase in the number of theoretical stages, as a rule, is increased to provide the necessary degree of purity of the crude target product according to the invention can, is, for example, using a small, and therefore, more economical distillation column (i.e. with a small number of theoretical stages of separation) for longer periods of their operation.

If n systems reactor oxidation (n is ≥2) operate in accordance with the proposed invention in a way such that the combined stream contains the target compounds obtained in all n systems of reactors, oxidation, according to the invention is favorable this difference in the duration of the operating periods n catalysts loaded in the n reactor systems oxidation to differences between consecutive durations were mostly the same and was not match any of the two consecutive durations.

In the present invention proposes a method of obtaining at least one target organic compounds below in a slightly modified formulation, which includes:

a) heterogeneously catalyzed vapor-phase partial oxidation of at least one source of organic compounds by molecular oxygen in two parallel operating systems reactor oxidation with you loaded catalysts, leading to the formation of two threads get gas, matched with the public containing the target compound and respectively formed in one of two oxidation reactors, and

b) subsequent allocation of at least one target compound from two threads get gas with the formation of a single thread crude target product,

according to which

c) before allocating two flow produced gas, or in the process of separating the two containing the target product downstream, if necessary, formed during the conversion of two threads get gas in one thread crude target product, and/or after discharge flows of crude target product formed in the process of separation of the two streams of received gas are mixed with each other in mixed flow,

characterized in that

one of the two catalysts loaded in two parallel operating system reactor oxidation, contains a partial amount of the catalyst, the duration of the already implemented heterogeneously catalyzed vapor-phase partial oxidation in which more than all the other parts of the loaded catalyst.

In accordance with the proposed invention by way of more than one target organic compound, obviously, can be synthesized simultaneously. A relevant example is the partial oxidation of propane in the course of which, as a rule, simultaneous formation of acrolein and acrylic acid. Similar about what atom partial ammoxidation of propylene and/or propane may occur simultaneous formation of acrylic acid and Acrylonitrile, that is typical for the case when the selected content of ammonia in the reaction gas mixture below the corresponding stoichiometric amount. In accordance with another option for simultaneous reception of more than one target product can be used as the source of the reaction gas mixture containing more than one source connection. In conclusion, it should be noted that the principle proposed in the invention method can also be used for catalyzed synthesis of esters or engage in other catalytic reactions. According to the invention it is also important that always formed the target connection with the relevant specifications content side components.

The target organic compound primarily can be acrylic acid and/or methacrylic acid. Suitable alcohols (for example, a monatomic or polyatomic) first of all are the alkanols, in particular alkanols with 1 to 8 carbon atoms (especially saturated), that is, for example, methanol, ethanol, 2-ethylhexanol, n-butanol and/or tert-butanol.

Examples and comparative examples of the two-stage heterogeneously catalyzed vapor-phase partial oxidation of propylene to acrylic acid

(A) General structure of performing experiments

I. the Reactor of the first reaction is Tadei (oxidation of propylene to acrolein)

The reactor consisted of a double-walled cylinder made of special steel (surrounded by a cylindrical tank cylindrical guide tube). The thickness of the walls ranged from 2 to 5 mm.

The internal diameter of the cylindrical tank was 91 mm, an Inner diameter of the guide tube was about 60 mm

Double-walled cylinder top was sealed with a lid, bottom, bottom.

Contact tube made of special steel (total length 400 cm, internal diameter 26 mm, outer diameter 30 mm, wall thickness 2 mm) was placed in the inside of the cylindrical tank cylindrical guide tube so that the contact tube protrudes from the upper and lower sides of the cylindrical tank, compressed with the corresponding lid and bottom. The fluid (molten salt consisting of 53% of the mass. potassium nitrate, 40% of the mass. sodium nitrite and 7% of the mass. sodium nitrate) were joined with the guide tube cylindrical tank. To create a highly uniform thermal boundary conditions on the outer surface of the contact tube along its entire length (400 cm) coolant through the propeller pump is first passed through a cylindrical tank with a goal temperature of the latter, and then through the intermediate space between the guide pipe and contentneutral (to a temperature of the contact tube). Then molten salt out of the cylindrical tank.

The temperature was regulated as desired by means of an electric heater mounted on the outer jacket of the cylindrical tank. In other cases was carried out by air cooling.

Power reactor

Salt melt and the source of the reaction gas mixture 1 was passed through the single-stage reactor parallel (if you look at the reactor top). The source of the reaction gas mixture 1 was entered in the contact tube from below. The temperature is introduced into the contact tube of the reaction gas mixture was 165°C.

Salt melt at a temperature Teinshe also brought in a cylindrical guide tube from the bottom and out of it from above with a temperature Tausexceeding its temperature at the inlet (Tein) by the amount of up to 2°C. the temperature of the molten salt inlet (Tein), which is about 320°C, have always relied so that in a single transmission of the reaction gas mixture through the contact tube, the degree of conversion of propylene in all cases was 97,5±0,1 mol%.

Filling the contact tubes (bottom to top)

The area And length of 90 cm was filled steatite balls with a diameter of 4 to 5 mm, forming a preliminary bulk layer.

Plot of length 100 which m was filled with a catalyst, which is a homogeneous mixture of 30 wt%, staticobj rings with dimensions of 5 mm × 3 mm × 2 mm (external diameter × length × internal diameter) and 70% of the mass. a solid catalyst, forming a similar plot With the catalyst.

Plot With a length of 200 cm was filled with a solid catalyst in the form of rings with dimensions of 5 mm × 3 mm × 2 mm (external diameter × length × internal diameter), obtained according to example 1 of German patent application DE-A 10046957 (stoichiometric composition [Bi2W2O9×2WO3]0,5[Mo12Co5,5Fe2,94Si1,59K0,08Ox]1).

Section D length of 10 cm was filled steatite rings with dimensions of 7 mm × 3 mm × 4 mm (external diameter × length × internal diameter), forming the final bulk layer.

Two reactors of the type specified above operated in parallel.

II. Intermediate cooling and possible intermediate oxygen (as air)

Streams of gases generated in both the reactor of the first reaction stage, with the aim of the intermediate cooling (through indirect heat exchange with the air) jointly passed through the connecting tube made of stainless steel (length 40 cm, internal diameter 26 mm, outer diameter 30 mm, wall thickness 2 mm; the tube is wrapped with insulating material with a thickness of 1 cm) in the middle part of which is 20 cm long melpomaen inert bulk layer of staticobj rings with dimensions of 7 mm × 3 mm × 4 mm (external diameter × length × internal diameter), that was Y-shaped prihlasovani directly to the contact tubes of the first reaction stage.

The temperature of the mixture flow of the gaseous products at the entrance to the connecting tube was more than 320°C, while the temperature at the outlet of the connecting tube corresponded to the interval from 200 to 270°C.

At the end of the connecting tube to the cooled mixture flows gaseous products if necessary, you can add air, compressed to the pressure of the mixed flow. Two equal parts formed by this reaction gas mixture 2 was entered directly into two parallel spaced contact tube intended for the implementation of the second reaction stage, which is also Y-shape was prepracovan the other end above the connecting tube.

III. The reactors of the second reaction stage (oxidation acrolein in acrylic acid)

Used reactors filled with stationary contact layer tubes, in a structural sense, is similar to the above reactor of the first reaction stage. Salt melt and the source of the reaction gas mixture were also received in each of the reactors in parallel (if you look at the reactor top). Molten salt in the guide tube, and the source of the reaction gas mixture 2 in the contact tube was also filed the bottom. The temperature of the molten salt inlet (Tein), which is about 263°C, continuously regulated so that in all cases when a single transmission of the reaction gas mixture has been achieved the degree of transformation of acrolein, component of 99.3±0,1 mol%. The temperature of the salt melt at the exit of the reactor (Taus) was higher than the inlet temperature (Tein) by the amount of up to 2°C.

Filling the contact tubes (bottom to top)

The area And length of 70 cm was filled steatite rings with dimensions of 7 mm × 3 mm × 4 mm (external diameter × length × internal diameter), forming a preliminary bulk layer.

The land In the length of 100 cm was filled with catalyst, which is a homogeneous mixture of 30% of the mass. staticobj rings with dimensions of 7 mm × 3 mm × 4 mm (external diameter × length × internal diameter) and 70% of the mass. shell catalyst similar to the catalyst forming section C.

Plot With a length of 200 cm was filled shell catalyst in the form of rings with dimensions of 7 mm × 3 mm × 4 mm (external diameter × length × internal diameter), obtained according to example 5 of German patent application DE-A 10046928 (stoichiometric composition Mo12V3W1,2Cu2,4Ox).

Section D 30 cm long filled steatite balls with a diameter of 4 to 5 mm, forming the final nasypna the layer.

IV. Selection of acrylic acid from the mixture obtained in the second reaction stage gas flows

Both obtained in the second reaction stage of the gas stream were combined, the resulting flow of gaseous products were subjected to in the separator Venturi direct cooling water with a temperature of 4°C, containing as a polymerization inhibitor hydroquinone in a concentration of 350 million-1mass. (Venturi same design, the acceleration of the gas mixture in the most narrowest point of the Venturi, the simultaneous injection of cooling water and intensive mixing in a turbulent flow field with high pressure losses; the separation of the liquid phase in the subsequently attached to the separator), and the resulting mixture was directed into the separator with the purpose of separation of the liquid phase. The separated aqueous phase was passed through a heat exchanger and recycled to the separator Venturi (360 l/h). Excess aqueous phase is continuously taken out from the system.

Mixed gas stream is cooled to a temperature of 30°C, were reported in the lower part of the absorption column with eleven nozzle plates with a diameter of 12 mm and the same distance between them, constituting 54 mm, in the upper part of which a counter-current was applied is used as the absorbent, stabilized with hydroquinone and cooled to a temperature of 2°C modus flow 1,10 kg/H. From the cube absorption column was collected 1.7 kg/h of aqueous acrylic acid concentration of about 40% of the mass. Emerging from the upper part of the absorption column residual gas if necessary sent for incineration and/or as a recycled gas used for forming the source of the reaction gas mixture 1 (clutched compressor and returned to the reactor, designed to implement the first reaction stage).

C) the Results obtained depending on the loaded catalyst and the composition of the starting reaction gas mixture

Comparative example 1

In both reactor of the first reaction stage and both reactor of the second reaction stage was loaded with fresh catalyst.

The source of the reaction gas mixture is sent to both the reactor of the first reaction stage, had the following composition:

5,3% about. propylene,

2,4% about. water,

0,7% about. components different from propylene, water, oxygen, and nitrogen,

molecular oxygen in an amount corresponding molar respect to propylene of 1.52:1, and

molecular nitrogen (up to 100% vol.).

Consumption of propylene over a catalyst loaded in the contact tube both reactors of the first stage was 110 nl/l·h as a source of fresh oxygen used air. One volume percent of the fresh propylene in the original reacts the availability of the gas mixture corresponds to 8.0%. the recirculated gas. The mixture flows gaseous products formed in the first reaction stage, introduced secondary air. The amount of secondary air was calculated so that its relation to fresh propylene was 1.45:1 (in nl). In accordance with this residual oxygen content in the formed in the second reaction stage gaseous product was 3.0%. The pilot plant is continuously operated in this mode during the period, was more than 28 weeks. Table 1 shows the selectivity of the formation of the target product (acrylic acid) SAAdepending on the duration of operation of the experimental setup (in weeks), and the selectivity of the formation of by-products: acetic acid, (SHAc) and formaldehyde (SF), respectively, in mol%. in terms of converted propylene, depending on the duration of operation of the experimental setup (all data refer to products of the second reaction stage). In addition, table 1 shows the molar ratio of acrylic acid to acetic acid (V) in aqueous absorbate.

Table
Duration of operationSAA SHAcSFV
Starting time86,821,243,4
4881,91,146,3
888,71,81,05to 49.3
1289,41,750,9551,4
16to 89.91,70,952,4
2090,31,650,8554,7
2490,81,620,8256,0
2891,21,60,857

After the respective division subject containing the target product water absorbet with respect to V, components 43,4.

Example 1

At the beginning of the synthesis was repeated comparative example 1. After without interruption process performed in accordance with comparative example 1, was synthesized 2200 kg of acrylic acid, the process was stopped and the catalyst is loaded in only one of the two reactor systems two-stage oxidation, was replaced by a similar but fresh catalyst. Then continued synthesis similarly to comparative example 1. Received after the interrupt process results depending on the duration of operation of the experimental setup (in weeks) are shown in table 2.

Table
Duration of operationSAASHAcSFV
Starting time891,71,052,4
489,61,60,956
889,9/td> 1,60,956,2
1290,21,60,9of 56.4
1690,51,50,860,3
2090,71,50,8of 60.5
2491,01,50,860,7
2891,21,50,860,8

Subsequent separation of the subject only contains the target product water absorbet with respect to V, components 52,4.

Comparative example 2

Repeated comparative example 1 (when diluted catalyst of the plot In the second reaction stage comprising 40 wt. -%), however, coming to the first reaction stage, the gas mixture had the following composition:

7,3% about. propylene,

10% about. water,

0,7% about. components different from propylene, water, to the of Sloboda and nitrogen,

molecular oxygen in an amount corresponding to the molar ratio of the propylene 1,73:1, and

molecular nitrogen (up to 100% vol.).

The secondary air was added. One volume percent of the fresh propylene in the source of the reaction gas mixture corresponds to 3.5%. the recirculated gas.

The results of the experiment depending on the duration of operation of the experimental setup (in weeks) are shown in table 3.

Table 3
Duration of operationSAASHAcSFV
Starting time86,72,251,35a 38.5
487,92,151,25of 40.9
888,72,051,243,3
1289,321,1 44,7
16to 89.51,951,0545,9
2090,11,9147,4
2490,31,870,9748,3
2890,61,850,9549,0

Subsequent separation of the subject containing the target product water absorbet with respect to V, the components of 38.5.

Example 2

At the beginning of the synthesis was repeated comparative example 2. After without interruption process performed in accordance with comparative example 1, was synthesized 2200 kg of acrylic acid, the process was stopped and the catalyst is loaded in only one of the two reactor systems two-stage oxidation, was replaced by a similar but fresh catalyst. Then continued synthesis similarly to comparative example 2. Received after the interrupt process results depending on lifespan the particular operation of the experimental setup (in weeks) are shown in table 4.

Table 4
Duration of operationSAASHAcSFV
Starting timeand 88.82,11,242,3
489,42,01,144,7
889,81,91,147,3
1290,11,91,047,4
1690,21,91,047,5
2090,51,81,050,3
2490,61,8 0,950,3
2890,81,80,950,4

Subsequent separation of the subject only contains the target product water absorbet with respect to V, the components of 42.3.

The method according to paragraphs 13-18 of the claims is the basis, for example, for the application proposed in the invention method.

Preliminary descriptions of applications for U.S. patent number 60/656,881 (filed 01.03.2005) and number 60/670,289 (filed 12.04.2005) is incorporated into the present application by reference. These descriptions may contain numerous changes and differences in comparison with the present description. In this regard, it should be assumed that the implementation of the invention in accordance with the following formula may differ from these preliminary descriptions.

1. The method of producing acrolein, acrylic acid, methacrolein or methacrylic acid as the target product
a) heterogeneously catalyzed vapor-phase partial oxidation of at least one source of organic compounds selected from propylene, propane, isobutylene, isobutane, acrolein or methacrolein, molecular oxygen in at least two parallel operating systems reactor on which islene with you loaded catalysts, leading to the formation of at least two threads get gas, respectively containing the target compound and respectively formed in one of the at least two oxidation reactors, and
b) subsequent isolation of the target product of at least two threads get gas with the formation of at least one thread crude target product, in accordance with which
c) before allocating at least two of the at least two threads of this gas are mixed with each other in the mixed stream, and
in case the event as the operation changes the selectivity of the formation of the target product and/or by-products, not all, at least two parallel operating systems reactor oxidation, which formed contained in the mixed flow of the target products, in parallel replaced with fresh catalyst entire quantity or partial quantity of a catalyst.

2. The method according to claim 1, characterized in that at least one of the catalysts loaded in at least two parallel-functioning system of oxidation reactors, which were formed contained in the mixed flow of the target products, contains at least a partial quantity of the catalyst, the duration of the already implemented the heterogeneous catalizer the wow vapor-phase partial oxidation of at least 30 calendar days more than all parts of the at least one other of the loaded catalyst.

3. The method according to claim 1 or 2, characterized in that carried out heterogeneously catalyzed vapor-phase partial oxidation in two parallel operating systems reactor oxidation and isolation of the target product from the mixed flow of the two product streams.

4. The method according to claim 1 or 2, wherein the heterogeneously catalyzed vapor-phase partial oxidation is a two-stage heterogeneously catalyzed partial oxidation of propylene to acrylic acid.

5. The method according to claim 1 or 2, wherein the heterogeneously catalyzed vapor-phase partial oxidation is a one-stage heterogeneously catalyzed partial oxidation of propane to acrylic acid.

6. The method according to claim 1 or 2, wherein the heterogeneously catalyzed vapor-phase partial oxidation is a two-stage heterogeneously catalyzed partial oxidation of isobutene to methacrylic acid.

7. The method according to claim 1 or 2, characterized in that at least two parallel-functioning system of oxidation reactors consist of two parallel functioning dual tubular reactors.

8. The method according to claim 4, characterized in that the catalyst of the first reaction stage include polymetallic oxide mass, the content is the following molybdenum (Mo), bismuth (Bi) and iron (Fe).

9. The method according to claim 4, characterized in that the catalyst of the second reaction stage include polymetallic oxide mass containing molybdenum (Mo) and vanadium (V).

10. The method according to claim 8, characterized in that the catalyst of the second reaction stage include polymetallic oxide mass containing molybdenum (Mo) and vanadium (V).

11. The method according to claim 1 or 2, characterized in that the allocation of at least one target product of at least two threads get gas includes fractionation condensation.

12. The method according to claim 1 or 2, characterized in that the allocation of at least one target product of at least two threads get gas includes the absorption.

13. The method of producing acrolein, acrylic acid, methacrolein or methacrylic acid as the target product heterogeneously catalyzed vapor-phase partial oxidation of at least one source of organic compounds selected from propylene, propane, isobutylene, isobutane, acrolein or methacrolein, molecular oxygen in at least two parallel operating systems reactor oxidation with you loaded catalysts, leading to the formation of at least two threads get gas, respectively containing the target product and, accordingly, on razuysya in one of the at least two oxidation reactors, and at first form a common thread is the source of the reaction gas mixture containing at least one of the original organic compound, which is then through the distribution system send at least two parallel-functioning system of oxidation reactors, and in the case of what is happening as the operation changes the selectivity of the formation of the target product and/or by-products, not all, at least two parallel operating systems reactor oxidation, which formed contained in the mixed flow of the target compounds simultaneously replaced with fresh catalyst entire quantity or partial quantity of a catalyst.

14. The method according to item 13, wherein at least one of the catalysts loaded in at least two parallel operating system reactor oxidation comprises at least a partial quantity of the catalyst, the duration of the already implemented heterogeneously catalyzed vapor-phase partial oxidation, in which at least 30 calendar days more than on all parts at least another of the loaded catalyst.

15. The method according to item 13 or 14, wherein the heterogeneously catalyzed vapor-phase partial oxidation is a two-stage heterogeneously catalyzed partially the oxidation of propylene to acrylic acid.

16. The method according to item 13 or 14, wherein the heterogeneously catalyzed vapor-phase partial oxidation is a one-stage heterogeneously catalyzed partial oxidation of propane to acrylic acid.

17. The method according to item 13 or 14, characterized in that at least two parallel-functioning system of oxidation reactors consist of two parallel functioning dual tubular reactors.

18. The method according to item 15, wherein the catalyst of the first reaction stage include polymetallic oxide mass containing molybdenum (Mo), bismuth (Bi) and iron (Fe), and the catalyst of the second reaction stage include polymetallic oxide mass containing molybdenum (Mo) and vanadium (V).



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to a method of conducting a continuous process of producing acrolein, acrylic acid or mixture thereof from propane in a stable operating mode, according to which: A) propane in a first reaction zone A undergoes heterogeneously catalysed dehydrogenation in the presence of molecular oxygen to obtain a gaseous mixture of products A containing propane and propylene, B) the gaseous mixture of products A, if needed, is fed into a first separation zone A in which a portion or more of components different from propane and propylene is separated therefrom and a gaseous mixture of products A' containing propane and propylene remaining after separation is obtained, C) the gaseous mixture of products A or gaseous mixture of products A' is fed into at least one oxidation reactor of the second reaction zone B, in which propylene contained therein undergoes partial selective heterogeneously catalysed gas-phase oxidation with molecular oxygen to obtain a gaseous mixture of products B, which contains acrolein, acrylic acid or mixture thereof as the desired product, unconverted propane, excess molecular oxygen and, if needed, unconverted propylene, D) in the second separation zone B, the desired product contained therein is separated from the gaseous mixture of products B, and at least a portion of the remaining gas containing propane, molecular oxygen and, if needed, unconverted propylene is returned to the reaction zone A as circulation gas 1 containing molecular oxygen, E) fresh propane is fed into at least one continuous flow process zone selected from a group comprising reaction zone A, separation zone A, reaction zone B and separation zone B, where the said fresh propane is fed at a rate characterised by a given stationary value when realising the process in a stable operating mode, and F) content of molecular oxygen in the gaseous mixture of products B is continuously determined and said value is compared with the desired stationary value needed to realise the process in stable operating mode, characterised by that if at a certain moment in time, content of molecular oxygen in the gaseous mixture of products B exceeds the given desired stationary value, fresh propane is fed into the process right away at feed rate higher than its stationary value, and if at a certain moment in time, content of molecular oxygen in the gaseous mixture of products B is lower than the corresponding given desired stationary value, fresh propane is fed into the process right away at feed rate lower than its stationary value.

EFFECT: used of present method reduces heat loss and prevents a drop in degree of dehydrogenation when producing acrolein, acrylic acid or mixture thereof from propane.

13 cl, 2 ex, 1 dwg

FIELD: chemistry.

SUBSTANCE: according to method A) an input stream of the reaction gaseous mixture A is fed into the input of the first reaction zone A, where the input stream is obtained by merging at least four different gaseous initial streams 1, 2, 3 and 4, where the gaseous initial streams 1 and 2 contain propane, gaseous initial stream 4 is molecular hydrogen and gaseous initial stream 3 is fresh propane, the input stream of the reaction gaseous mixture A is passed at least through one catalyst layer of the first reaction zone A on which, if needed, when feeding other gaseous streams, as a result of heterogeneous catalytic partial dehydrogenation of propane, a stream of products of gaseous mixture A forms, which contains propane and propylene, the stream of products of gaseous mixture A comes out of the first reaction zone A through the corresponding outlet, while splitting said stream into two partial streams 1 and 2 of products of the gaseous mixture A with identical composition, and the partial stream 1 of products of the gaseous mixture A is returned to the first reaction zone A as the gaseous initial stream 1, the partial stream 2 of products of the gaseous mixture A, if needed, is directed to the first separation zone A, in which a portion or more of components contained therein, which are different from propane and propylene, are separated, as a result of which a stream of products of gaseous mixture A' which contains propane and propylene, B) partial stream 2 of products of the gaseous mixture A or a stream of products of gaseous mixture A' is used in a second reaction zone B for supplying at least one oxidation reactor, in which propylene contained in the partial stream 2 of products of gaseous mixture A or in the stream of products of gaseous mixture A' undergoes selective heterogeneously catalysed partial gas-phase oxidation with molecular oxygen to obtain a stream of products of a gaseous mixture B, which contains acrolein, acrylic acid or mixture thereof as the desired product, unconverted propane and, if needed, unconverted propylene, as well as molecular oxygen, the stream of products of gaseous mixture B comes out of reaction zone B, the desired product contained in separation zone B is separated in said separation zone B and at least a portion of residual gas formed after separation and containing unconverted propane, molecular oxygen and, if needed, unconverted propylene, is returned to reaction zone A as gaseous initial stream 2. Gaseous initial streams 2, 3 and 4 as well as, if needed, additional gaseous initial streams different from the gaseous initial stream 1, are merged into a gaseous stream of the working mixture, after which, using this gaseous stream of the working mixture as the working stream, a jet pump is activated, said pump having a nozzle, a mixing section, a diffuser and a suction inlet. Movement of the working stream which is throttled through the nozzle, the mixing section and the diffuser to the input of the first reaction zone A, as well as the suction effect of the suction inlet takes place in the direction of outlet of the stream of products of gaseous mixture A from the first reaction zone A. The pressure drop created in the suction nozzle with splitting of the stream of products of the gaseous mixture A into two partial streams 1 and 2 results in suction of the partial stream 1 of products of the gaseous mixture A, its movement through the diffuser with simultaneous mixture with the working stream on the mixing section and inlet of the formed reaction stream of gaseous mixture A at its inlet point into the first reaction zone A, characterised by that a gaseous initial mixed stream is formed first by merging in random sequence gaseous initial streams 2 and 3, as well as, if needed, additional gaseous initial streams different from gaseous initial streams 1 and 4, and only after that the gaseous initial stream 4 is added to the formed gaseous initial mixed stream to obtain a gaseous mixed working stream.

EFFECT: used of present method reduces heat loss and prevents a drop in degree of dehydrogenation when producing acrolein, acrylic acid or mixture thereof from propane.

7 cl, 4 ex, 4 dwg

FIELD: chemistry.

SUBSTANCE: initial mixture 2 of the reaction gas which contains propylene and molecular oxygen, as well as molecular nitrogen and propane as inert gases - diluents, in which molar ratio of molecular oxygen to propylene O2:C3H6≥1, at high temperature is passed through a fixed catalyst bed, the active mass of which is at least one polymetallic oxide containing Mo, Fe and Bi, in which the initial mixture 2 of the reaction gas, per total volume, contains 7-9 vol. % propylene, 9.8-15.5 vol. % molecular oxygen, 10.5-15.5 vol. % propane and 40-60 vol. % molecular nitrogen, provided that the molar ratio V1 of propane contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.5 and 2.2, molar ratio V2 of molecular nitrogen contained in the initial mixture 2 of the reaction gas to molecular oxygen contained in the initial mixture 2 of the reaction gas is between 3.5 and 4.5, and molar ratio V3 of molecular oxygen contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.4 and 2.14.

EFFECT: improved method of lowering flash point temperature of a fixed catalyst bed during synthesis of acrolein or acrylic acid or mixture thereof through heterogeneously catalysed gas-phase partial oxidation of propene.

27 cl, 1 dwg, 3 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of lowering the flash point temperature of a fixed catalyst bed during synthesis of acrylic acid through heterogeneously catalysed gas-phase partial oxidation of propylene, in which a) at the first reaction step, propane undergoes heterogeneously catalysed dehydrogenation to obtain a product gas mixture 1, b) a partial amount of components in the formed product mixture 1 which are different from propane and propylene are converted to other compounds if needed and if needed a partial amount of components of the product gas mixture 1 formed at the first reaction step which are different from propane and propylene are separated, wherein a product gas mixture 1', which contains propane and propylene, as well as compounds different from oxygen, propane and propylene, is obtained from the product gas mixture 1, and c) as a component of the initial reaction gas mixture 2 at the second reaction step, the product gas mixture 1 or 1' undergoes heterogeneously catalysed partial oxidation in the gas phase of propylene contained in the product gas mixture 1 or 1' to acrolein, where the product gas mixture 2 is obtained, and d) temperature of the product gas mixture leaving the second reaction step, if needed, is lowered through direct and/or indirect cooling and molecular oxygen and/or inert gas is added to the said mixture 2 if needed, and e) further, as an initial reaction gas mixture 3 at the third reaction step, acrolein contained in the initial reaction gas mixture 3 undergoes heterogeneously catalysed gas-phase partial oxidation to acrylic acid, where the product gas mixture 3 is obtained, and f) acrylic acid and at least unreacted propane and propylene contained in the product gas mixture 3 are separated from the product gas mixture 3 in a separation zone A an then returned to at least the first of three reaction steps, where i) the second reaction step is carried out until achieving propylene degree of conversion Up ≤99 mol % for one-time passage through the zone, and ii) the third reaction step is carried out until achieving acrolein degree of conversion UA ≥96 mol % for one-time passage through the zone. The method involves at least one separate selection for components different from propane and propylene, which contains propane and propylene in amount ≤5 vol %.

EFFECT: low temperature.

39 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing acrylic acid from propylene, involving a first step where propylene is oxidised to acrolein and a second step where acrolein is oxidised to acrylic acid, as well as a step for dehydrating glycerin to acrolein in the presence of a propylene-containing gas. The said step for dehydrating glycerin is carried out before catalytic oxidation of propylene to acrolein in the presence of the supplied propylene-containing gas, or after catalytic oxidation of propylene to acrolein in the presence of a gaseous mixture coming out after oxidation of propylene to acrolein.

EFFECT: method enables partial use of renewable material, while increasing output of acrylic acid.

8 cl, 5 dwg, 6 ex

FIELD: chemistry.

SUBSTANCE: in accordance with the method A) at least two propane-containing gas supply streams are fed into the first reaction zone A, where at least one of the said streams contains fresh propane, and propane fed into this reaction zone undergoes heterogeneous catalytic dehydrogenation with a fixed bed catalyst, obtaining a propane- and propylene-containing gaseous mixture of products A, B) which is extracted from reaction zone A, in the first separation zone, A is separated from at least a portion of components contained in it, which are different from propane and propylene, and the remaining gaseous mixture of products A' which contains propane and propylene C) is used in the second reaction zone B for supplying at least one oxidation reactor, and propylene contained in the gaseous mixture of products A' in at least one oxidation reactor undergoes heterogeneous catalytic two-step gas-phase partial oxidation with molecular oxygen to acrylic acid or a mixture of acrolein and acrylic acid as an end product, as well as to an excess molecular oxygen-containing gaseous mixture of products B, D) which is extracted from the reaction zone B, in the second separation zone B, the end product contained in it is extracted through absorption or fractional condensation, and at least a portion of the remaining residual gas which contains unconverted propane, molecular oxygen, and also if necessary, unconverted propylene are recycled into the reaction zone A as at least one of two propane-containing supply streams, where the said recycling into the reaction zone A is done along the path of the heterogeneous catalysed dehydrogation of propane in that reaction zone such that, at the point for feeding the recycled gas into reaction zone A at least 5 mol % of propane has already undergone dehydrogenation, where the said propane is fed into this reaction zone with other supply streams, where molar ratio of the propylene contained in the reaction gaseous mixture to molecular hydrogen contained in the said mixture within the reaction zone A does not exceed 10.

EFFECT: design of an improved method of obtaining acrolein, acrylic acid or their mixture from propane.

41 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of continuous, heterogeneous, catalytic, partial gas-phase oxidation of at least one organic compound selected from a group comprising propene, acrolein, isobutene, methacrolein, isobutene and propane, in an oxidation reactor loaded with a gas mixture which, along with at least one compound to undergo partial oxidation and molecular oxygen as an oxidation agent, includes at least one diluent gas which is essentially inert in conditions of heterogeneous, catalytic, gas-phase partial oxidation, where the source of oxygen and inert gas for the loaded gas mixture is air which is compressed in a compressor beforehand from a low initial pressure value to a high final pressure value, where before entering the compressor, the air undergoes at least one mechanical separation procedure through which particles of solid substance dispersed in the air can be separated.

EFFECT: method prevents negative effect of solid particles on the air compression stage, undesirable increase in pressure loss and reduction of activity or selectivity of the catalyst.

21 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method for prolonged heterogeneously catalysed partial oxidation of propene to acrylic acid in gaseous phase, in which the initial gaseous reaction mixture 1, containing propene, molecular oxygen and at least one inert gas, where molecular oxygen and propene are in molar ratio O2:C3H6≥1, is first passed through a fixed catalyst bed 1 at high temperature at the first stage of the reaction, where the active mass of the catalysts is at least one multimetal oxide, containing molybdenum and/or tungsten, as well as at least one element from a group consisting of bismuth, tellurium, antimony, tin and copper, so that, conversion of propene in a single passage is ≥93 mol % and associated selectivity of formation of acrolein, as well as formation of acrylic acid by-product together is ≥90 mol %, temperature of the product gaseous mixture 1 leaving the first reaction stage is reduced if necessary through direct and/or indirect cooling, and if necessary, molecular oxygen and/or inert gas is added to the product gaseous mixture 1, and after that, the product gaseous mixture 1, acting as initial reaction mixture 2, which contains acrolein, molecular oxygen and at least one inert gas, where molecular oxygen and acrolein are in molar ratio O2:C3H4O≥0.5, is passed through a second fixed catalyst bed 2 at high temperature at the second reaction stage, where the active mass of the catalysts is at least one multimetal oxide, containing molybdenum and vanadium so that, conversion of acrolein in a single passage is ≥90 mol % and selectivity of the resultant formation of acrylic acid at both stages is ≥80 mol % in terms of converted propene, and temperature of each fixed catalyst bed is increased independently of each other. Partial oxidation in gaseous phase is interrupted at least once and at temperature of fixed catalyst bed 1 ranging from 250 to 550°C and temperature of fixed catalyst bed 2 ranging from 200 to 450°C, gaseous mixture G, which consists of molecular oxygen, inert gas and water vapour if necessary, is first passed through fixed catalyst bed 1, and then, if necessary, through an intermediate cooler and then finally through fixed catalyst bed 2, in which at least a single interruption takes place before temperature of the fixed catalyst bed 2 increases by 8°C or 10°C, wherein prolonged increase of temperature by 8°C or 10°C, is possible when virtual passage of temperature of the fixed catalyst bed in the period of time on the leveling curve running through the measuring point using the Legendre-Gauss method of the least sum of squares of errors, temperature increase of 7°C or 10°C is achieved.

EFFECT: method increases service life of catalyst.

24 cl, 1 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to improvement of the method of producing (meth)acrylic acid or (meth)acrolein through gas-phase catalytic oxidation of at least one oxidisable substance, chosen from propylene, propane, isobutylene and (meth)acrolein, molecular oxygen or a gas, which contains molecular oxygen, using a multitubular reactor, with such a structure that, there are several reaction tubes, with one (or several) catalytic layer (catalytic layers) in the direction of the axis of the tube, and a coolant can flow outside the said reaction tubes so as to regulate temperature of reaction, in which temperature of the said reaction of gas-phase catalytic oxidation is increased by varying temperature of the coolant at the inlet for regulating temperature of the reaction, while (1) temperature of coolant at the inlet for regulating temperature of the reaction is varied by not more than 2°C for each variation as such, and (2) when variation is done continuously, the time interval from the variation operation, directly preceding the present, is not more than 10 minutes, and, in addition, the difference between the maximum value of peak temperature of reaction of the catalyst layer of the reaction tube and temperature of the coolant at the inlet for regulating temperature of reaction is not less than 20°C.

EFFECT: method in which sharp increase of temperature is suppressed even after changing reaction conditions with aim of increasing temperature for improving efficiency, thus preventing catalyst deactivation, and achieving stable output.

3 cl, 5 dwg, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of carrying out heterogenous catalytic partial oxidation in gas phase of acrolein into acrylic acid, during which reaction gas mixture, containing acrolein, molecular oxygen and at least one inert gas-thinner, is passed through having higher temperature catalytic still layer, whose catalysts are made in such way that their active mass contains at least one oxide of multimetal, containing elements Mo and V, and in which during time, temperature of catalytic still layer is increased, partial oxidation in gas phase being interrupted at least once and at temperature of catalytic still layer from 200 to 450°C acrolein-free, containing molecular oxygen, inert gas and, if necessary, water vapour, as well as, if necessary, CO, gas mixture of G oxidative action is passed through it, at least one interruption being performed before increase of catalytic still layer temperature constitutes 2°C or 4°C or 8°C or 10°C during a long period of time, temperature increase constituting 2°C or 4°C or 8°C or 10°C over a long period of time occurring when in plotting factual course of temperature of catalytic still layer during time on laid through measurement points equation curve according to elaborated by Legendre and Gauss method of the least sum of error squares 2°C or 4°C or 8°C or 10°C temperature increase is achieved.

EFFECT: ensuring spread of hot point with time which is less than in previous methods.

21 cl, 3 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of separating acrylic acid and methacrylic acid in case of a liquid phase P containing acrylic and methacrylic acid, where content of acrylic acid is at least 50 wt % and where said liquid phase contains acrylic acid and methacrylic acid in molar ratio V from 3:2 to 100000:1, wherein separation is carried out via crystallisation, where acrylic acid is concentrated in the formed crystallised product while methacrylic acid is concentrated in the obtained residual melt.

EFFECT: method enables efficient separation of acrylic acid from methacrylic acid.

6 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: according to the method: A) at least two initial gas streams containing propane, which form the reaction gas A, are fed into a reaction zone A, where one of said gas streams contains fresh propane; the reaction gas A is passed through at least one catalyst layer in reaction zone A in which partial heterogeneously catalysed dehydrogenation of propane results in formation of molecular hydrogen and propylene; molecular oxygen is fed into reaction zone A and oxidises molecular hydrogen in the reaction gas A to water vapour, and a gaseous product A is collected from reaction zone A, said product containing molecular hydrogen, water vapour, propylene and propane; B) the gaseous product A collected from the reaction zone A, while feeding molecular oxygen, is used in reaction zone B to supply at least one oxidation reactor with reaction gas B which contains molecular hydrogen, water vapour, propane, propylene and molecular oxygen, and propylene contained in reaction gas B undergoes two-step heterogeneously catalysed partial gas-phase oxidation in reaction zone B to obtain a gaseous product B containing acrylic acid as the end product, unconverted propane, molecular hydrogen, water vapour and carbon dioxide as by-products, as well as other secondary components with boiling point lower or higher the boiling point of water; C) gaseous product B is output from the reaction zone B and acrylic acid, water and secondary components with boiling point higher than that of water contained therein are separated in a first separation zone I through fractional condensation or absorption, wherein the residual gas I contains unconverted propane, carbon dioxide, molecular hydrogen, secondary components with boiling point lower than that of water, as well as, if necessary, propylene and molecular oxygen not converted in reaction zone B; D) residual gas I undergoes further treatment by washing carbon dioxide contained therein, separation of a partial amount of residual gas I, as well as, if necessary, separation of molecular hydrogen contained in the residual gas I using a separating membrane; E) after further treatment, unconverted propane-containing residual gas I is returned to reaction zone A as at least one of at least two propane-containing initial streams, where in reaction zone A, a certain amount (M) of molecular hydrogen is oxidised to water vapour, which makes up at least 35 mol % but not more than 65 mol % of the total amount of molecular hydrogen produced in reaction zone A and, if necessary, fed into said reaction zone A.

EFFECT: improved method of producing acrylic acid from propane.

22 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of conducting a continuous process of producing acrolein, acrylic acid or mixture thereof from propane in a stable operating mode, according to which: A) propane in a first reaction zone A undergoes heterogeneously catalysed dehydrogenation in the presence of molecular oxygen to obtain a gaseous mixture of products A containing propane and propylene, B) the gaseous mixture of products A, if needed, is fed into a first separation zone A in which a portion or more of components different from propane and propylene is separated therefrom and a gaseous mixture of products A' containing propane and propylene remaining after separation is obtained, C) the gaseous mixture of products A or gaseous mixture of products A' is fed into at least one oxidation reactor of the second reaction zone B, in which propylene contained therein undergoes partial selective heterogeneously catalysed gas-phase oxidation with molecular oxygen to obtain a gaseous mixture of products B, which contains acrolein, acrylic acid or mixture thereof as the desired product, unconverted propane, excess molecular oxygen and, if needed, unconverted propylene, D) in the second separation zone B, the desired product contained therein is separated from the gaseous mixture of products B, and at least a portion of the remaining gas containing propane, molecular oxygen and, if needed, unconverted propylene is returned to the reaction zone A as circulation gas 1 containing molecular oxygen, E) fresh propane is fed into at least one continuous flow process zone selected from a group comprising reaction zone A, separation zone A, reaction zone B and separation zone B, where the said fresh propane is fed at a rate characterised by a given stationary value when realising the process in a stable operating mode, and F) content of molecular oxygen in the gaseous mixture of products B is continuously determined and said value is compared with the desired stationary value needed to realise the process in stable operating mode, characterised by that if at a certain moment in time, content of molecular oxygen in the gaseous mixture of products B exceeds the given desired stationary value, fresh propane is fed into the process right away at feed rate higher than its stationary value, and if at a certain moment in time, content of molecular oxygen in the gaseous mixture of products B is lower than the corresponding given desired stationary value, fresh propane is fed into the process right away at feed rate lower than its stationary value.

EFFECT: used of present method reduces heat loss and prevents a drop in degree of dehydrogenation when producing acrolein, acrylic acid or mixture thereof from propane.

13 cl, 2 ex, 1 dwg

FIELD: chemistry.

SUBSTANCE: according to method A) an input stream of the reaction gaseous mixture A is fed into the input of the first reaction zone A, where the input stream is obtained by merging at least four different gaseous initial streams 1, 2, 3 and 4, where the gaseous initial streams 1 and 2 contain propane, gaseous initial stream 4 is molecular hydrogen and gaseous initial stream 3 is fresh propane, the input stream of the reaction gaseous mixture A is passed at least through one catalyst layer of the first reaction zone A on which, if needed, when feeding other gaseous streams, as a result of heterogeneous catalytic partial dehydrogenation of propane, a stream of products of gaseous mixture A forms, which contains propane and propylene, the stream of products of gaseous mixture A comes out of the first reaction zone A through the corresponding outlet, while splitting said stream into two partial streams 1 and 2 of products of the gaseous mixture A with identical composition, and the partial stream 1 of products of the gaseous mixture A is returned to the first reaction zone A as the gaseous initial stream 1, the partial stream 2 of products of the gaseous mixture A, if needed, is directed to the first separation zone A, in which a portion or more of components contained therein, which are different from propane and propylene, are separated, as a result of which a stream of products of gaseous mixture A' which contains propane and propylene, B) partial stream 2 of products of the gaseous mixture A or a stream of products of gaseous mixture A' is used in a second reaction zone B for supplying at least one oxidation reactor, in which propylene contained in the partial stream 2 of products of gaseous mixture A or in the stream of products of gaseous mixture A' undergoes selective heterogeneously catalysed partial gas-phase oxidation with molecular oxygen to obtain a stream of products of a gaseous mixture B, which contains acrolein, acrylic acid or mixture thereof as the desired product, unconverted propane and, if needed, unconverted propylene, as well as molecular oxygen, the stream of products of gaseous mixture B comes out of reaction zone B, the desired product contained in separation zone B is separated in said separation zone B and at least a portion of residual gas formed after separation and containing unconverted propane, molecular oxygen and, if needed, unconverted propylene, is returned to reaction zone A as gaseous initial stream 2. Gaseous initial streams 2, 3 and 4 as well as, if needed, additional gaseous initial streams different from the gaseous initial stream 1, are merged into a gaseous stream of the working mixture, after which, using this gaseous stream of the working mixture as the working stream, a jet pump is activated, said pump having a nozzle, a mixing section, a diffuser and a suction inlet. Movement of the working stream which is throttled through the nozzle, the mixing section and the diffuser to the input of the first reaction zone A, as well as the suction effect of the suction inlet takes place in the direction of outlet of the stream of products of gaseous mixture A from the first reaction zone A. The pressure drop created in the suction nozzle with splitting of the stream of products of the gaseous mixture A into two partial streams 1 and 2 results in suction of the partial stream 1 of products of the gaseous mixture A, its movement through the diffuser with simultaneous mixture with the working stream on the mixing section and inlet of the formed reaction stream of gaseous mixture A at its inlet point into the first reaction zone A, characterised by that a gaseous initial mixed stream is formed first by merging in random sequence gaseous initial streams 2 and 3, as well as, if needed, additional gaseous initial streams different from gaseous initial streams 1 and 4, and only after that the gaseous initial stream 4 is added to the formed gaseous initial mixed stream to obtain a gaseous mixed working stream.

EFFECT: used of present method reduces heat loss and prevents a drop in degree of dehydrogenation when producing acrolein, acrylic acid or mixture thereof from propane.

7 cl, 4 ex, 4 dwg

FIELD: chemistry.

SUBSTANCE: initial mixture 2 of the reaction gas which contains propylene and molecular oxygen, as well as molecular nitrogen and propane as inert gases - diluents, in which molar ratio of molecular oxygen to propylene O2:C3H6≥1, at high temperature is passed through a fixed catalyst bed, the active mass of which is at least one polymetallic oxide containing Mo, Fe and Bi, in which the initial mixture 2 of the reaction gas, per total volume, contains 7-9 vol. % propylene, 9.8-15.5 vol. % molecular oxygen, 10.5-15.5 vol. % propane and 40-60 vol. % molecular nitrogen, provided that the molar ratio V1 of propane contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.5 and 2.2, molar ratio V2 of molecular nitrogen contained in the initial mixture 2 of the reaction gas to molecular oxygen contained in the initial mixture 2 of the reaction gas is between 3.5 and 4.5, and molar ratio V3 of molecular oxygen contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.4 and 2.14.

EFFECT: improved method of lowering flash point temperature of a fixed catalyst bed during synthesis of acrolein or acrylic acid or mixture thereof through heterogeneously catalysed gas-phase partial oxidation of propene.

27 cl, 1 dwg, 3 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: initial mixture 2 of the reaction gas which contains propylene and molecular oxygen, as well as molecular nitrogen and propane as inert gases - diluents, in which molar ratio of molecular oxygen to propylene O2:C3H6≥1, at high temperature is passed through a fixed catalyst bed, the active mass of which is at least one polymetallic oxide containing Mo, Fe and Bi, in which the initial mixture 2 of the reaction gas, per total volume, contains 7-9 vol. % propylene, 9.8-15.5 vol. % molecular oxygen, 10.5-15.5 vol. % propane and 40-60 vol. % molecular nitrogen, provided that the molar ratio V1 of propane contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.5 and 2.2, molar ratio V2 of molecular nitrogen contained in the initial mixture 2 of the reaction gas to molecular oxygen contained in the initial mixture 2 of the reaction gas is between 3.5 and 4.5, and molar ratio V3 of molecular oxygen contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.4 and 2.14.

EFFECT: improved method of lowering flash point temperature of a fixed catalyst bed during synthesis of acrolein or acrylic acid or mixture thereof through heterogeneously catalysed gas-phase partial oxidation of propene.

27 cl, 1 dwg, 3 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of lowering the flash point temperature of a fixed catalyst bed during synthesis of acrylic acid through heterogeneously catalysed gas-phase partial oxidation of propylene, in which a) at the first reaction step, propane undergoes heterogeneously catalysed dehydrogenation to obtain a product gas mixture 1, b) a partial amount of components in the formed product mixture 1 which are different from propane and propylene are converted to other compounds if needed and if needed a partial amount of components of the product gas mixture 1 formed at the first reaction step which are different from propane and propylene are separated, wherein a product gas mixture 1', which contains propane and propylene, as well as compounds different from oxygen, propane and propylene, is obtained from the product gas mixture 1, and c) as a component of the initial reaction gas mixture 2 at the second reaction step, the product gas mixture 1 or 1' undergoes heterogeneously catalysed partial oxidation in the gas phase of propylene contained in the product gas mixture 1 or 1' to acrolein, where the product gas mixture 2 is obtained, and d) temperature of the product gas mixture leaving the second reaction step, if needed, is lowered through direct and/or indirect cooling and molecular oxygen and/or inert gas is added to the said mixture 2 if needed, and e) further, as an initial reaction gas mixture 3 at the third reaction step, acrolein contained in the initial reaction gas mixture 3 undergoes heterogeneously catalysed gas-phase partial oxidation to acrylic acid, where the product gas mixture 3 is obtained, and f) acrylic acid and at least unreacted propane and propylene contained in the product gas mixture 3 are separated from the product gas mixture 3 in a separation zone A an then returned to at least the first of three reaction steps, where i) the second reaction step is carried out until achieving propylene degree of conversion Up ≤99 mol % for one-time passage through the zone, and ii) the third reaction step is carried out until achieving acrolein degree of conversion UA ≥96 mol % for one-time passage through the zone. The method involves at least one separate selection for components different from propane and propylene, which contains propane and propylene in amount ≤5 vol %.

EFFECT: low temperature.

39 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of lowering the flash point temperature of a fixed catalyst bed during synthesis of acrylic acid through heterogeneously catalysed gas-phase partial oxidation of propylene, in which a) at the first reaction step, propane undergoes heterogeneously catalysed dehydrogenation to obtain a product gas mixture 1, b) a partial amount of components in the formed product mixture 1 which are different from propane and propylene are converted to other compounds if needed and if needed a partial amount of components of the product gas mixture 1 formed at the first reaction step which are different from propane and propylene are separated, wherein a product gas mixture 1', which contains propane and propylene, as well as compounds different from oxygen, propane and propylene, is obtained from the product gas mixture 1, and c) as a component of the initial reaction gas mixture 2 at the second reaction step, the product gas mixture 1 or 1' undergoes heterogeneously catalysed partial oxidation in the gas phase of propylene contained in the product gas mixture 1 or 1' to acrolein, where the product gas mixture 2 is obtained, and d) temperature of the product gas mixture leaving the second reaction step, if needed, is lowered through direct and/or indirect cooling and molecular oxygen and/or inert gas is added to the said mixture 2 if needed, and e) further, as an initial reaction gas mixture 3 at the third reaction step, acrolein contained in the initial reaction gas mixture 3 undergoes heterogeneously catalysed gas-phase partial oxidation to acrylic acid, where the product gas mixture 3 is obtained, and f) acrylic acid and at least unreacted propane and propylene contained in the product gas mixture 3 are separated from the product gas mixture 3 in a separation zone A an then returned to at least the first of three reaction steps, where i) the second reaction step is carried out until achieving propylene degree of conversion Up ≤99 mol % for one-time passage through the zone, and ii) the third reaction step is carried out until achieving acrolein degree of conversion UA ≥96 mol % for one-time passage through the zone. The method involves at least one separate selection for components different from propane and propylene, which contains propane and propylene in amount ≤5 vol %.

EFFECT: low temperature.

39 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention discloses a method for safe continuous heterogeneous catalysed gas-phase partial oxidation of at least one organic starting compound in a reactor, whose stream of loaded gas mixture along with at least one partially oxidisable organic starting compound and molecular oxygen as an oxidising agent contains at least one diluting gas which remains essentially inert under heterogeneous catalysed gas-phase partial oxidation conditions,and is obtained by merging at least two different initial streams, where through online measurement of concentration of one or more selected components in the stream of the loaded gas mixture in one or more initial streams which form the stream of the loaded gas mixture and/or stream of gas mixture of the product, loading of an uncontrolled stream of gas mixture in terms of explosion risk or other is prevented, wherein for online measurement of the partial stream, the analysed gas stream is accordingly continuously fed into the measurement cell of an analysing device and during measurement, said stream comes out of the measurement cell into the free atmosphere, where the analysed gas stream and/or free atmosphere are subject to pressure fluctuations, where the effect of pressure fluctuation of the analysed gas stream and/or free atmosphere on the measured pressure in the measurement cell in the analysing device and therefore on the measurement resulta) is corrected through calculation, based on properties capable of correlation with the gas in the measurement cell and/or b) is minimised based on that the measured in the measurement cell of the analysing device is kept constant or controlled to a constant value using a pressure regulator, independent of the pressure of the analysed gas stream and/or free atmosphere.

EFFECT: high reliability and safety of the process.

18 cl, 4 ex, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing acrylic acid from propylene, involving a first step where propylene is oxidised to acrolein and a second step where acrolein is oxidised to acrylic acid, as well as a step for dehydrating glycerin to acrolein in the presence of a propylene-containing gas. The said step for dehydrating glycerin is carried out before catalytic oxidation of propylene to acrolein in the presence of the supplied propylene-containing gas, or after catalytic oxidation of propylene to acrolein in the presence of a gaseous mixture coming out after oxidation of propylene to acrolein.

EFFECT: method enables partial use of renewable material, while increasing output of acrylic acid.

8 cl, 5 dwg, 6 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method for selective oxidation of D-glucose in aqueous solution by bubbling pure oxygen at atmospheric pressure in the presence of an alkalising agent and a catalyst containing nano-dispersed particles of ruthenium metal on a support, where the support is super-crosslinked polystyrene which is pre-saturated with a ruthenium salt RuOHCl3 with concentration of 1.100-111.1 mg/l. The disclosed method can be used in chemical, food and pharmaceutical industry to obtain calcium gluconate and D-arabinose.

EFFECT: method enables to obtain a salt of D-gluconic acid with output of approximately 95% with retention of high activity and stability of the catalyst for 15 working cycles.

2 cl, 7 ex, 1 tbl

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