Catalyst to obtain a vinyl acetate in the fluidized bed

 

(57) Abstract:

The invention relates to a catalyst for the receipt of vinyl acetate in the fluidized bed. Describes the catalyst used in the preparation of vinyl acetate monomer from ethylene, acetic acid and oxygen-containing gas in the fluidized bed comprising porous microspheroidal particles of the medium containing the catalytically active palladium crystallites, finely dispersed within the carrier. To save this catalytic material activity and selectivity does not require the introduction of gold. The method of preparation of the catalyst fluidized bed to obtain a vinyl acetate in which the catalytically active fine palladium crystallites finely dispersed within the carrier, includes dispersion within the carrier selected metal-containing material that exhibits an affinity for palladium, obtaining vysokodispersnyh crystallites of palladium. Showing affinity metal-containing material can be dispersed impregnation prior microspheroidal particles of the carrier or can be deeply inserted into the media prior to the impregnation of soluble palladium material is soderzhaschego gas with the above catalyst in the reactor with a fluidized bed in the reaction conditions of the fluidized bed. Effect: the preservation of the activity and selectivity of the catalyst without the need for the presence of gold. 4 C. and 32 C.p. f-crystals, 1 table.

This application is a partial continuation of patent application U.S. 09/207851, filed December 8, 1998 and is incorporated into this description by reference.

Background of invention

The present invention relates to a catalyst and a carrier for a catalyst that can be used to obtain vinyl acetate monomer (YOU) in the fluidized bed, in particular to an active and selective catalyst for getting YOU in the fluidized bed, suitable for use in the reactor with a fluidized bed, and the catalytically active metal is well dispersed in the carrier of the catalyst.

Vinyl acetate monomer are usually obtained in the gas phase reaction of ethylene, acetic acid and oxygen in the presence of the catalyst on the carrier in the reactor with a fixed bed. In a reactor of this type of media, such as silicon dioxide or alumina, is impregnated with a catalytic metal such as palladium, in combination with the gold and salt of an alkali metal, usually in the form of acetate. The requirement that the present is zgotovlen in the form of relatively large structural elements, such as balls, the diameter of which may range 2-50 mm or more.

According to well-known publications related to the catalysts of the fixed layer, palladium and gold are distributed more or less evenly across the media (see, for example, US 3275680, US 3743607, US 3950400, GB 1333449 and patent South Africa 687990). Since the gaseous reagents in large catalytic structural elements in a noticeable extent not diffuse, a large number of expensive metal-containing catalytic components inside the catalyst is unused. Were created the catalysts of the fixed layer in which a large part of the catalytic metals were applied to the outer shell of the elements of the catalyst on the carrier. For example, in the patent GB 1500167 described catalytic structure in which at least ninety percent of palladium and gold spread on the area of the carrier particles, which accounts for no more than thirty percent of the radius of the particle in the direction from its surface. In addition, in patent GB 1283737 States that the degree of penetration into porous media can be regulated by pretreatment of the porous carrier with a solution of a compound of an alkali metal, for example, ka other methods of preparation of the catalyst-impregnated membrane described in patents US 4087622 and US 5185308. The catalysts impregnated with a shell that includes, in addition to palladium and gold, items such as compounds of the lanthanides, presented in the patent US 5859287 and WO 99/29418. In the preparation of other catalysts of the fixed layer, described in EP-A 0723810, before adding palladium and gold kremmidiotis carrier may be impregnated with a salt of metal of group IA, IIA, IIIA or IVB and then calcined. Each of these publications relates to the preparation of the catalyst fixed layer, which can be used to obtain vinyl acetate.

A new way to produce vinyl acetate monomer is application carried out in the fluidized bed method in which gaseous reactants are continuously in contact with the small particles of the catalyst on the carrier in a fluidized bed conditions. The advantages of the method of obtaining YOU in the fluidized bed are simpler reactor design for fluidized bed than novotrubnogo reactor with a fixed layer, and increase the service life of the catalyst by reducing the number of hot spots that are typical for a reactor with a fixed bed. Moreover, the continuous introduction of fresh catalyst pozvolyaet. Due to the fact that oxygen in a reactor with a fluidized bed can be administered safely in higher concentrations without forming the combustible mixture, it is possible to achieve higher performance. In patents US 5591688, US 5665667 and US 5710318 described the preparation of the catalyst of receipt of vinyl acetate in the fluidized bed or the method of producing vinyl acetate in the fluidized bed.

In any case, the usual technically acceptable catalyst to get YOU no matter if they use in reactor systems with a fixed or fluidized bed, includes gold in combination with materials containing metal palladium such as described in patent US 5859287 and published application EP 0723810, which are included in the present description as a reference. I believe that gold forms with palladium alloy and prevents agglomeration or sintering of the palladium particles during the lifetime of the catalyst in the process conditions. Although as substitutes for gold in the catalytic systems were encouraged to use other metals, it was found that taking into account such factors as the activity and selectivity of the catalyst in the form of particles require gold. the need to create a technically efficient catalyst, the presence of gold in which it would not be mandatory or minimized.

In addition, there remains a need for catalysts receive YOU, first of all catalysts for fluidized bed, which would have a more effective activity/selectivity and which would be more resistant to abrasion. As mentioned in the present description, the proposed catalyst and a carrier for the catalyst have the necessary from a technical point of view the characteristics of the activity/selectivity without the use of gold as a catalytic component. Moreover, in normal conditions, the fluidized bed of catalytic particles of the present invention, generally more resistant to abrasion.

Summary of the invention

The catalytically active material, which can be used for vinyl acetate monomer from ethylene, acetic acid and oxygen-containing gas in the fluidized bed includes a porous microspheroidal media containing catalytically active palladium crystallites, finely dispersed in the carrier. This catalytic material does not require the introduction of gold for modereadwrite layer, in the exercise of which the catalytically active fine palladium crystallites are finely dispersed in the carrier, includes the dispersion of the selected metal-containing material in a carrier that exhibits affinity for palladium, obtaining highly dispersed crystallites of palladium. Possessing affinity metal-containing materials can be dispersed by impregnation of a pre-cooked microspheroidal media or can be deeply introduced into a carrier prior to the impregnation of soluble palladium materials.

Description of the preferred embodiments of the invention

The catalysts of receipt of vinyl acetate of the present invention, which can be used in a reactor system with a fluidized bed include catalytically active palladium crystallites, finely dispersed in microspheroidal media. I believe that small finely dispersed crystallites retain catalytic activity and selectivity without the necessity of introducing into the catalytic material of gold.

According to one of embodiments of the present invention the catalytically active palladium crystallites injected into cauie crystallites were well dispergirovannykh in the inner zone of the particle. In the preferred catalysts are palladium crystallites contained in the inner zone of the catalytic particles, rather than being concentrated on the surface. Although the concentration of the palladium crystallites may vary from the bottom of the surface layer to the center of the particles on the TEM-micrograph of palladium crystallites seem to be subtly dispergirovannykh, i.e., palladium crystallites almost evenly distributed in the inner zone without explicit agglomerations. Compared to particles prepared similarly by using palladium and gold, which are characterized by the presence of a significant number of agglomerated Pd/Au crystallites, the preferred catalytic particle of the present invention is distinguished by a small number of agglomerated palladium crystallites, if they are available.

The average diameter of the palladium crystallites in the catalyst particles according to the invention generally does not exceed about 20 nanometers (nm). In the preferred catalysts of the present invention, the reduced size of the metal crystallites in the catalyst particle, including palladium crystallites are less than about 15 nm, more preferably less than about 10 nm. RA is Isperih palladium crystallites inside microspheroidal material carrier in accordance with the present invention a metal material, which connects palladium or exhibits thereto affinity, should be well dispersed within the particles of the medium. These manifest affinity metal materials include lanthanides, such as lanthanum and cerium, and the metals of group 3 and group 4 (Periodic system of elements IUPAC), such as titanium and zirconium. Unlike gold, which when used produces an alloy of gold/palladium, these showing the affinity of the metals when they are well dispersed in the particles of the medium do not form agglomerates of palladium crystallites. Thus, in the absence of agglomeration of palladium crystallites should have more surface area available as catalytic sites.

One of the methods of preparation of catalytically active materials on carriers offer in accordance with the present invention, includes the introduction of solutions of palladium and add exhibiting affinity metal-containing material into contact with a pre-prepared media in the form of particles. All metal-containing materials must be completely soluble in the environment of acceptable solvent, preferably in water, at a temperature low enough to need a kitchen is storytime metal-containing materials is carried out at room temperature. Therefore, the solvent in the quality of the environment and the metal-containing material is chosen in such a way as to achieve complete solubility, preferably at room temperature, in particular at 10-40S, usually at 20-30C. As discussed below, the impregnated carrier recover from getting inside the carrier particles of the metal crystallites, which are considered to be catalytically active sites. In a preferred embodiment, after impregnation should the recovery phase, although in order to simplify the handling of materials can be provided intermediate drying of the catalytic particles. There is no need to "fix" soluble metal salts in alkaline media materials that is required before recovering in the preparation of catalysts with a "shell" for the fluidized bed.

In another method of preparation of catalytically active material on the media showing the affinity of the metal are uniformly dispersed throughout the material of the carrier in contrast to the impregnation of the pores of the support of a simple physical mixture of two materials or exhibiting affinity metal-containing materials with subsequent calcination. For example, when cooking on the shining affinity metal, such as cerium oxide, titanium oxide or zirconium oxide can be typed into a colloidal solution of silicic acid in the preparation of media. In a preferred method, before spray drying, in which are formed the pre-formed particles of the medium used in the present invention, the oxide exhibiting affinity metal replaces part kremmidiotis particles introduced into the colloidal solution of silicic acid. In another preferred embodiment, in the preparation of pre-formed particles of the carrier for catalyst may be used in the Sol of oxide exhibiting affinity metal. In a pre-prepared media used in the present invention, it is possible to introduce a mixture of oxides exhibiting affinity of metals. In pre-cooked carriers for catalysts of the present invention, including homogeneous distributed oxides exhibiting the affinity of the metal oxide exhibiting the affinity of the metal oxide is a part of the porous structure of the media.

In yet another variant solutions exhibiting affinity metal-containing materials can be impregnated with a pre-formed particles of the carrier, with, the which can be used according to the present invention, is applied to the material in the form microspheroidal particles suitable for carrying out the process in the fluidized bed. As is well known in the technology of fluidized bed, the particles should be sufficiently small that the reaction conditions they could be kept in a fluidized state and at the same time have sufficient resistance to abrasion, which during the process there was no need to replace excessive amounts of catalyst. Moreover, although the typical size of the particles should not be so large (the size of the particles is determined by their average diameters) to their retention in fluidized condition was due to technological difficulties, should not be excessive number of very small particles (fines) that are difficult to remove from the system and which can clog the gas recirculation line. Thus, the size of a typical acceptable catalytic particles of the fluidized bed is divided between the larger and smaller particles within certain limits on the sizes of these particles.

When implementing the method according to the present izmery at least 75% of the particles are less than about 105 microns, more preferably a size of at least 85% of the particles are less than about 105 microns. In a typical catalyst, which can be used according to the present invention, the proportion of particles larger than 105 microns, less than 1-5%. Moreover, the size of less than 50% of the particles, as a rule, are less than 44 microns, and preferably smaller than 35% of the particles is less than 44 microns. A typical catalyst may include approximately 25-30% of particles smaller than 44 microns. A typical catalyst, which can be used according to the present invention includes at least a 50% average particle diameter in the range 44-88 μm. For specialists in the art it is obvious that the particle size of 44, 88 and 105 μm are randomly selected dimensions in the sense that they are based on cell sizes of standard sieves. The particle size and distribution of particle size can be determined by using an automatic laser device, such as a Microtrac 100.

Microspheroidal particles, which can be used according to the present invention have sufficient porosity to allow diffusion of the gaseous reagents in the particle and contact with the catalytic sites in the s had the opportunity to diffusion. However, a particle with an excessively large pore volume, as a rule, does not have sufficient resistance to abrasion or does not have sufficient surface area for catalytic activity. Pore volume (determined by mercury porometry) acceptable microspheroidal particles typically ranges from about 0.2 to 0.7 cm3/g pore Volume preferred particles is in the range from about 0.3 to 0.65 cm3/g, more preferably in the range from about 0.4 to 0.55 cm3/,

Specific surface area (determined by BET method) of particles with an average diameter and pore volume, which can be used according to the present invention, generally greater than about 50 m2/g and can be up to about 200 m2/, Typical specific surface area according to the measurement ranges from about 60 to about 125 m2/,

Although the media on kremmidiotis basis are the most preferred of the present invention, can be used and other oxides, if only the prepared particles have the appropriate dimensions and a sufficient volume of pores, giving you the ability to place the required catalytic materials. Possible LASS="ptx2">Commonly used carriers, primarily kremmidiotis media, presented in the patent US 5591688, which is included in the present description by reference. If these carriers microspheroidal particle is prepared by spray drying a mixture of a colloidal solution of silicic acid with particles of silicon dioxide, followed by drying and calcining. In the cooking process with the silicon dioxide in the form of particles are mixed at 10 wt.%, preferably at least 50 wt.%, a colloidal solution of silicic acid. Acceptable silicon dioxide in the form of particles is white carbon black, such as the product of Aerosil® (Degussa Chemical Company). Typical kremmidiotis material in the form of particles is characterized by a high specific surface area (approximately 200 m2/g) in the almost complete absence of micropores and, as a rule, consists of aggregates with an average diameter of several hundred nanometers) of individual particles of average diameter of about 10 nm (7 nm). The preferred silicon dioxide free of sodium. Silicon dioxide in the form of particles injected into the mixture in sufficient amount to achieve the target volume of pores in the resulting particle media. The amount of silicon dioxide in the form of particles mastervile 10-50 wt.%. Usually a mixture of a colloidal solution of silicic acid/silicon dioxide in the form of particles spray dried at an elevated temperature of about 115-280S, preferably 130-S, followed by calcining at a temperature, which is typically 550-700C, preferably 630-S.

According to one of embodiments of the present invention a portion of the silicon dioxide in the form of particles can be replaced exhibiting affinity metal-containing material such as cerium oxide, titanium dioxide, zirconium dioxide or oxide of lanthanum. These oxides, as a rule, replace 0.5 to 20 wt.% or more, preferably 1-5 wt.% silicon dioxide in the form of particles.

Alternatively colloidal solution may be prepared from oxide other than silicon dioxide, or in combination with silicon dioxide. In this embodiment, the powdered oxide is added to a colloidal solution, such as a colloidal solution of cerium oxide, titanium dioxide, zirconium dioxide, as described above for kremmidiotis materials, and the resulting mixture is dried by spraying with obtaining pre-prepared particles of the carrier for catalyst. As the powdery material can be used dioxide Krumlov, the only prerequisite is that showing the affinity of the metal must also be distributed in the particles sufficiently for the preparation of the catalyst according to the invention. The final particle must be microspheroidal and porous, as indicated above, and must include a showing affinity metal, well distributed throughout the catalyst particle, so that the introduction of palladium and subsequent recovery was ensured distribution of palladium crystallites in accordance with the present invention.

Although the preparation of catalysts according to the invention, generally, may not require the presence of gold for activity and selectivity, gold can be added as an optional component, primarily with a view to maintaining long-term stability or integrity. Gold may be appropriate component in the catalytic particle, which in the process of obtaining exhibiting affinity metal (e.g., CE) enter into a pre-prepared media. However, the amount of gold in this case, as a rule, less the amount in which it is used in conventional catalysts, the content in to the 2">Featured colloidal solution of silicic acid, which can be used according to the present invention includes particles of silicon dioxide in the colloidal solution of the mean diameter, usually more than 20 nm, and their size can reach about 100 nm or more. The preferred colloidal solutions include particles of silicon dioxide ranging in size from about 40 to 80 nm. Especially preferred colloidal solution of silicic acid Nalco 1060, as particles of silicon dioxide are relatively large average sizes in the package 60 nm less effective than smaller particles of the colloidal solution, such as the product of Nalco 2327 with a particle size of about 20 nm. From the colloidal solution with larger particle sizes get the ultimate media with greater mesoporous volume and a lower volume of micropores.

Acceptable catalyst also includes a salt of an alkali metal (most preferably potassium) as a promoter in an amount up to about 10 wt.%, preferably 5-8 wt.%, more preferably up to about 4 wt.% (in terms of alkaline metal). The catalyst typically comprises at least 0.1 wt.%, more preferably at least 1 wt.% alkali metal. Typical ka the usual salt of an alkali metal add after impregnation with palladium material and subsequent recovery in the form of a solution, applying for regulating the amount of alkali metal salt applied to the catalytic particle, the method of initial moisture content. In another embodiment, the alkali metal can be introduced in the first impregnating solution.

The catalyst which can be used according to the present invention typically contains from at least about 0.1 wt.%, preferably at least 0.2 wt.% palladium to about 5 wt.%, preferably up to 4 wt.% palladium. As described above, for controlling the amount of palladium on the carrier in the preferred embodiment, palladium is introduced into the material of the carrier by the method of initial moisture content.

The number of exhibiting affinity metal comparable (though not necessarily equal) to the number of palladium, which must be entered in the catalyst. The catalyst may include from at least about 0.1 wt.%, preferably at least 0.2 wt.% showing the affinity of the metal to about 10 wt.% or more, preferably up to 5 wt.% this metal.

In the process of preparation of the catalyst according to the invention is introduced by impregnation into the carrier metal-containing materials such as palladium and terisolasi materials, restore back isomerase material becomes catalytically active palladium crystallites with zero valence [Pd(Oh)]. Typical reducing agents known in the art, include hydrogen, hydrides, alkanes, alkenes, hydrazine, etc., For recovery of the metal-containing material preferably using hydrazine (most preferably in aqueous solution). Preferably the restoration of water hydrazine after impregnation. To complete the reaction, typically use an excess of reductant.

In the preferred embodiment, to remove excess reducing agent, as well as unwanted anions, such as halides, soaked and restored catalytic particles are washed with appropriate solvents, such as water. Washing can be done several times with portions of the liquid to achieve the target pollutant impurities. Before adding a promoter such as potassium acetate, washed particles usually slowly dried.

The preferred method of preparation of the catalyst according to the present invention comprises the contacting of the solutions of palladium and at least one showing the affinity of the metal-containing material prior microspheroidal particles in porous media. The metal-containing material must be filled in particle carrier is not accumulated agglomerates of metal-containing material. In a preferred embodiment, the impregnation of soluble metal-containing material is carried out at room temperature. Thus, the solvent in the quality of the environment and the metal-containing material is chosen in such a way as to achieve complete solubility, preferably at room temperature. Commonly used metal salts include the halides, and the typical solvent is deionized or distilled water. Typical soluble salts, which can be used in the present invention include salts of tetrachloropalladate acid, such as tetrachloropalladate sodium or potassium, palladium chloride or palladium chloride dihydrate, selenate palladium sulfate, palladium, tetraamminepalladium (III) chloride, etc., the Preferred tetrachloropalladate. Similarly can be used other soluble metal salts as showing affinity metal-containing materials, such as chlorides, bromides, iodides, nitrates. Typically use a halide salt, preferably the chloride salt. Because the acetate salt of palladium and showing the affinity of metals in water or in acetic acid is moderately soluble, when performing the present invention, these salts, as Estim methods. Preferred impregnation solutions of salts is the method of initial moisture content, which measure the amount of salt solution required to fill the pores of the carrier without the use of excess solution. In this way the target amount of palladium and other metal-containing materials can be applied to the carrier by calculating the number of metals and volume of solution required to fill the pores. Because solutioned media, as a rule, give slowly to dry without rinsing, the media usually do all metals impregnating solution.

When performing a typical method prior microspheroidal particles of the carrier impregnated with the solution (or solutions) salts of metals (palladium and at least one showing the affinity of metal) with initial moisture content. Connection active metal, palladium and showing affinity metal-containing component in the respective ratios are dissolved in appropriate solvent. Next, in a solution containing the catalytically active metal (Pd) and exhibiting affinity metal-containing material is injected material carrier and mix, allowing the impregnated material noiselessators slowly dried at elevated temperature, such as 40-80C, usually during the night. In a preferred embodiment, the impregnated metal-containing materials restore to get active palladium crystallites, washed to remove halide and a reducing agent and dried. The dried material is injected into a second solution containing promoter salt of an alkali metal, preferably potassium acetate. This second solution is heated to evaporate the solvent to obtain a dried catalyst as set forth above. The final dry catalyst can be applied upon receipt of vinyl acetate from raw materials, in the preferred embodiment comprising ethylene, acetic acid and oxygen-containing gas in a reactor system with a fluidized bed.

In a preferred embodiment, impregnating salt as a metal-containing materials (Pd and showing affinity metals) dissolved in one portion of the solvent. The solvent is used in an amount such that the pore volume of the carrier was completely filled with the first solution. However, in some cases, a target exhibiting affinity metal-containing material may be insoluble substance which is a solvent used for other metal-containing compounds. This nm solution containing the other components. Acceptable solvents include water and volatile organic solvents such as carboxylic acids with four or fewer carbon atoms, alcohols, ethers, esters and aromatic compounds. The preferred solvent is water. In another embodiment showing the affinity of the metals can be applied on the finished catalyst by introducing exhibiting affinity of metals in the process of getting microspheroidal particle media.

The catalysts according to the invention can be used in the reactor with a fluidized bed for the interaction of ethylene and acetic acid with oxygen with the receipt of vinyl acetate in the reaction conditions of the fluidized bed. The reaction temperature, it is advisable to maintain a level from about 100 to S, preferably from 130 to 190C. Acceptable gauge the reaction pressure is from about 50 to 200 pounds per square inch (3-14 bar), preferably from 75 to 150 pounds per square inch (5-10 bar). In a reactor system with a fluidized bed of catalyst particles kept in the fluidized state by passing through the system sufficient gas flow. In a preferred embodiment, the speed of this gas state. Excessive flow rate may cause leakage of gas through the reactor, which reduces the efficiency of transformation. To maintain activity during the process you can add the additional amount to the promoter salt of an alkali metal.

Below the invention is illustrated in the examples, not limiting its scope.

Examples 1-9 and comparative experiment A.

To test the catalytic materials of the present invention conducted a series of conventional and comparative experiments. In these experiments, prior microspheroidal particles of the medium (described below either carrier 1 or carrier 2) was impregnated by the method of initial humidity aqueous solution of completely dissolved tetrachloropalladate sodium in combination with a water solution is completely dissolved selected compounds showing affinity metal. In accordance with this technology a measured amount of impregnating solution at ambient temperature was introduced into contact with the carrier in an amount which is determined only by the need to fill the pores of the carrier, without excess liquid. The final impregnated solid was dried at 60C overnight. The dried solid substance, the cat is built using 3 g of hydrazine hydrate is added and 80 ml of water) with the aim to restore these metal-containing materials, and the resulting solution was filtered and the solid material is washed several times with deionized water to remove residual hydrazine and chloride, which is confirmed by a test with silver nitrate. The resulting solid was dried at 60°C during the night and was additionally impregnated by the method of initial humidity aqueous solution of potassium acetate, taken in sufficient quantity for the introduction of the catalyst the target amount of potassium, and during the night were dried at 60C. Approximately two grams of the obtained catalytic material was combined with an inert diluent (CoE/or AI/A on the carrier 1, which was found, created in reaction inert conditions) to obtain a total of about 30 CC solids. All this solid was loaded into a microreactor, as set out below. The results presented in the table.

Preparation of media

Prepared in the examples according to the present invention used prior microspheroidal particle carriers of two types: (1) the media, which included 100% of silicon dioxide and (2) the media, including silicon dioxide in combination with other known inert carriers, such as aluminum oxide the catalysts used media with special distribution between particle sizes:

sizes 5% of particles are less than 105 microns, but exceed 88 µm

dimensions 70% of the particles are less than 88 microns, but exceed 44 µm

dimensions 25% of the particles are less than 44 microns.

Media 1

Medium 1 was prepared by spray drying a mixture of a colloidal solution of silicic acid Nalco 1060 (company Nalco Chemical Company) and silicon dioxide Degussa Aerosil® 200 (Degussa Chemical Company) in accordance with the patent US 5591688. In the process of drying medium 80% silicon dioxide passed from the colloidal solution, and 20% silicon dioxide passed from product Aerosil®. Dried dispersion of microspheres was caliciviral in air at C within 4 hours

The carrier 2

Some media were prepared by spray drying a mixture of a colloidal solution of silicic acid Nalco 1060 (company Nalco Chemical Company), silicon dioxide Degussa Aerosil® 200 (Degussa Chemical Company) and an additional oxide such as cerium oxide, titanium dioxide, zirconium dioxide, aluminum oxide and mixtures of silicon dioxide/aluminum oxide (such as products, Aerosil® MOX 170 or Aerosil® JUICE 84). In the process of drying medium 80% silicon dioxide passed from the colloidal solution, 20% silicon dioxide passed from product Aerosil® and 1-3 wt.% product Aerosil® was replaced by oxides of cerium or titanium. Dried races is e 4 o'clock

The test reactor

The prepared catalysts were tested in the reactor laboratory fluidized bed with a maximum capacity of the catalyst 40 cubic, see the Catalyst used in sufficient quantity to ensure that the degree of conversion of oxygen to limit to 30%, which allowed to compare the catalytic activity directly. The total amount of the loaded catalyst equal to 30 CC, was obtained by mixing the test in the reactor sufficient amount of the above-described inert material in the form microspheroidal particles with the active catalyst. The reactor was equipped with two holes for the intake of raw materials, and the ethylene, acetic acid, oxygen and some nitrogen was supplied to the reactor through the bottom inlet opening and through the Central inlet was filed only nitrogen.

The pressure in the reactor was regulated by the regulator back pressure, the temperature in the reactor was maintained at a level of S, and all the lines leading to the reactor and the exhaust from him, were equipped with heating means and the temperature maintained at 160±5C.

Otheriwse from the reactor effluent stream was analyzed using installed on the production line, the AK and playannouncement detector (PID). Oxygen, nitrogen, ethylene and carbon dioxide were separated in a column with molecular sieve H in parallel with 23% SP1700 on 80/100 Chromosorb PAW and quantitatively determined using TKD. The vinyl acetate and acetic acid were separated in a capillary column with 4% DP-1701 and quantitatively determined using the PID.

These data were calculated activity (in grams of the resulting vinyl acetate per kilogram of catalyst per hour) and selectivity (the number of moles of the resulting vinyl acetate per mole of the ethylene feedstock).

These data show that the catalysts of the present invention retain activity and selectivity without the need for the presence of gold. Moreover, the catalysts of the present invention, including cerium, during testing in the fluidized bed showed increased resistance to abrasion.

Although the invention is illustrated in the example of a specific variants of its implementation, for specialists in the art it is obvious that in such cases can make modifications and changes, without departing from the scope of the claims.

1. The method of preparation of the catalytic material used in obtaining the scientists porous microspheroidal particles of the carrier with solutions of palladium compound and at least one connection showing the affinity of the metal, so that palladium and showing affinity metal is finely dispersed in microspheroidal the particles of the medium; (II) the recovery of the palladium compound to Pd(0) -crystallites; (III) adding to the media promotor amount of salt of an alkali metal and (IV) the allocation of the obtained catalytic material.

2. The method according to p. 1, wherein prior microspheroidal particles of the medium is introduced into contact with the solutions haloesters salts of palladium and showing the affinity of metal.

3. The method according to any of the preceding paragraphs, in which you previously received microspheroidal particles of the medium is introduced into contact with a solution of a palladium compound and a solution of at least one of the compounds exhibiting the affinity of metal on separate stages.

4. The method according to any of the preceding paragraphs, wherein the oxide exhibiting affinity metal deeply injected into prior microspheroidal carrier particles to the impregnation of palladium compound.

5. The method according to any of the preceding paragraphs, in which you previously received microspheroidal carrier particles include silicon dioxide.

7. The method of preparation of the catalytic material used in the preparation of vinyl acetate in a reactor system with a fluidized bed comprising (I) pre-production of porous microspheroidal particles of the medium in which exhibiting affinity metal-containing material is homogeneous dispersed within these microspheroidal particles of the carrier; (II) contacting the pre-obtained porous microspheroidal particles of the carrier with solutions of palladium compounds such that the palladium metal is finely dispersed in microspheroidal the particles of the medium; (III) recovery of the palladium compound to PD(0)-crystallites; (IV) adding a promoter amount of a salt of an alkali metal and (V) the selection of the obtained catalytic material.

8. The method according to p. 7, in which the solution of the palladium compound is an aqueous solution.

9. The method according to p. 7 or 8, wherein the porous microspheroidal particles of the medium previously obtained by adding oxide exhibiting affinity metal with particles of silicon dioxide in the colloidal solution of silicic acid and spray drying OBR is a distant particles of the medium previously obtained by adding particles of silica in the Sol of oxide exhibiting a binding affinity for the metal and spray drying with formation of a porous microspheroidal particles.

11. The method according to p. 10, wherein the oxide exhibiting affinity metal with particles of silicon dioxide added to a colloidal solution.

12. The method according to p. 7 or 8, wherein the solution of at least one of the compounds exhibiting the affinity of the metal impregnated microspheroidal particles of the medium.

13. The method according to any of the preceding paragraphs, wherein displaying the affinity of the metal is a metal of group 3 or 4 or lanthanide.

14. The method according to any of the preceding paragraphs, wherein displaying the affinity of the metal is cerium or lanthanum.

15. The method according to any of the preceding paragraphs, wherein displaying the affinity of the metal is cerium.

16. The method according to any of paragraphs.1-13, wherein displaying the affinity of the metal is titanium or zirconium.

17. The method according to any of the preceding paragraphs, wherein the promoter salt of the alkali metal is potassium acetate.

18. The method according to any of the preceding paragraphs, wherein the catalytic material does not contain gold.

19. The method according to any of the preceding paragraphs, wherein the average diameter of the palladium crystallites are less than about 10 nm.

20. Kataliticheski active palladium crystallites, introduced in the structure microspheroidal particles of the medium together with the salt of an alkali metal as promoter and expressing the affinity component, where the palladium crystallites finely dispersed throughout the structure microspheroidal particles.

21. The catalyst according to p. 20, which does not contain gold.

22. The catalyst p. 20 or 21, in which the average diameter of the palladium crystallites are less than about 10 nm.

23. The catalyst according to any one of paragraphs.20-22, which includes an effective amount of at least one exhibiting affinity component, which is a metal of group 3 or 4 or lanthanide.

24. The catalyst according to any one of paragraphs.20-23, in which showing the affinity component is a lanthanum or cerium.

25. The catalyst according to any one of paragraphs.20-23, in which showing the affinity component is a titanium or zirconium.

26. The catalyst according to any one of paragraphs.20-25, in which the carrier is impregnated with exhibiting affinity component.

27. The catalyst according to any one of paragraphs.20-25, which manifests affinity component add an introduction to the media during preparation of the carrier.

28. The catalyst according to any one of paragraphs.20-27, which microspheroidal clubhome of PP.20-28, in which microspheroidal carrier particles consist of a porous silicon dioxide, which is characterized by the distribution of particle size, wherein the average diameter of at least 50% of the particles is less than 105 microns, and an average diameter of at least 50% of the particles is 44-88 microns.

30. The catalyst according to any one of paragraphs.20-29, in which the specific pore volume microspheroidal of the carrier particles is from about 0.2 to 0.7 cm3/,

31. The catalyst according to any one of paragraphs.20-30, in which the specific surface area microspheroidal particles of the medium exceeds about 50 m2/,

32. The catalyst according to any one of paragraphs.20-31, in which the porous prior microspheroidal carrier particles are composed of silicon dioxide with a specific pore volume in the range from about 0.3 to about 0,65 cm3/g, which as showing affinity component comprises cerium.

33. The catalyst according to any one of paragraphs.20-32, which includes from about 1 to 5 wt.% potassium.

34. The catalyst according to any one of paragraphs.20-33, in which at least a part of the cerium add the introduction of prior microspheroidal particles of the medium.

35. The catalyst according to any one of paragraphs.20-34, which is the procedure of obtaining vinyl acetate, comprising contacting ethylene, acetic acid and oxygen-containing gas with a catalyst prepared by the method according to any of paragraphs.1-19, or a catalyst according to any one of paragraphs.20-35 in the reactor with a fluidized bed in the reaction conditions of the fluidized bed.

 

Same patents:

The invention relates to the production of acetic acid
The invention relates to a method for producing vinyl acetate and a catalyst intended for use in this method

The invention relates to a method for producing vinyl acetate from ethylene, acetic acid and oxygen

The invention relates to a vapor-phase process for the preparation of vinyl acetate from ethylene, acetic acid and oxygen-containing gas

The invention relates to a method for producing vinyl acetate from ethylene, acetic acid and oxygen-containing gas

The invention relates to the extraction and reuse of ethylene upon receipt of vinyl acetate in the vapor phase

The invention relates to a method for preparing a catalyst which comprises a noble metal and a metal, which is the promoter of catalysis, in combination with the compound of the alkali or alkaline-earth metal deposited on the outer surface of the carrier

The invention relates to a method for preparing a catalyst which comprises a noble metal and a metal, which is the promoter of catalysis, in combination with the compound of the alkali or alkaline-earth metal deposited on the outer surface of the carrier

The invention relates to catalysts for production of vinyl acetate by reaction of ethylene, oxygen and acetic acid

The invention relates to a new method of preparation of the catalyst for vapor-phase reaction of ethylene, oxygen and acetic acid to form vinyl acetate, wherein said catalyst comprises metallic palladium and gold deposited on a suitable porous media
The invention relates to a method for producing vinyl acetate and a catalyst intended for use in this method

The invention relates to a vapor-phase process for the preparation of vinyl acetate from ethylene, acetic acid and oxygen-containing gas

The invention relates to a method for producing vinyl acetate from ethylene, acetic acid and oxygen-containing gas

The invention relates to the extraction and reuse of ethylene upon receipt of vinyl acetate in the vapor phase

The invention relates to methods of producing a catalyst containing metallic palladium and gold, to obtain a vinyl acetate by reaction of ethylene, oxygen and acetic acid, and a process for the production of vinyl acetate using the obtained catalyst

The invention relates to catalysts for production of vinyl acetate by reaction of ethylene, oxygen and acetic acid

The invention relates to a method for producing a catalyst for production of vinyl acetate by reaction of ethylene, oxygen and acetic acid containing porous media, porous surfaces of which is coated with an effective amount of copper, palladium and gold

The invention relates to an improved process for the preparation of vinyl acetate by reaction of ethylene, oxygen and acetic acid, used as reagents, including contacting the above reactants with a catalyst containing a porous medium, the porous surfaces of which is deposited catalytically effective amounts of metallic palladium and gold, copper in the form of free metal or copper acetate, and the fourth metal selected from the group consisting of magnesium, calcium, barium and zirconium, in the form of its oxide or mixture of oxide and free metal, at a temperature of 150-220oC and pressure up to 20 ATM

The invention relates to the discovery, before this time is appreciated that in the preparation of vinyl acetate using supported on a carrier catalyst containing palladium, gold and copper in which copper is essentially mixed with palladium or gold or both of these metals, the copper content in the catalyst during the lifetime of the catalyst tends essentially to decline, it is necessary previously to replace or regenerate the catalyst, the durability of which can approach or exceed two years

The invention relates to the refining and petrochemical industries, in particular to methods of producing catalysts for the conversion of aliphatic hydrocarbons2-C12in high-octane gasoline and/or aromatic hydrocarbons
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