Removal of reducing permanganate compounds from process of methanol carbonylation

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of reducing and/or removing reducing permanganate compounds (RPC), carboxylic acids C3-8 and C2-12 of alkyl iodide compounds, formed during carbonylation of a carbonylation-capable reagent, chosen from a group consisting of methanol, methylacetate, methyl formate, dimethyl ether and their mixture, into commercial-grade acetic acid, in which products of the said carbonylation include a volatile phase, which is distilled thereby obtaining purified commercial-grade acetic acid and the first distillate, containing methyl iodide, water and at least one reducing permanganate compound, where improvement includes stages: (a) separation of the obtained first distillate into a light and a heavy phase, with subsequent distillation of at least part of the light phase for obtaining a second distillate, containing methyl iodide, dimethyl ether and at least said one reducing permanganate compound, which is taken to the next distillation stage, where a stream is formed as distillate, containing reducing permanganate compound; (b) addition of dimethyl ether into supply of said stream containing reducing permanganate compound, and extraction of this stream with water to form the first raffinate and first aqueous extraction stream, containing at least said one reducing permanganate compound; and (c) extraction of the first raffinate with water to form the second raffinate and second aqueous extraction stream, containing at least said one reducing permanganate compound. Invention also relates to a method of separating a mixture, containing water, acetic acid, methyl iodide, methyl acetate, methanol and at least one reducing permanganate compound (RPC), obtained by separating the liquid-vapour phase of the output stream of the methaol carbonylation reactor to form a vapour phase and a liquid phase, distillation of the vapour phase to form a liquid product which contains acetic acid, and first distillate, condensation of at least part of the first distillate thereby obtaining a liquid composition which contains methyl acetate, methyl iodide, water, methanol and at least one reducing permanganate compound (RPC), separation of the obtained liquid composition into a light and a heavy phase, which includes methyl iodide, where the light phase is the said mixture, where the said method involves stages: (a) distillation of the mixture to obtain a second distillate which contains at least one reducing permanganate compound (RPC), which is taken for the next distillation stage, where a stream is formed as distillate, containing reducing permanganate compound and dimethyl ether; and (b) extraction of concentrated reducing permanganate compound with water, where stage (b) includes at least two consecutive extraction stages, where each extraction stage involves bringing concentrated reducing permanganate compound into contact with water and separation of the aqueous stream, containing at least said one reducing permanganate compound, where dimethyl ether is added to the said distillate stream concentrated with reducing permanganate compound before extraction of the concentrated reducing permanganate compound with water.

EFFECT: process is described for removing reducing permanganate compounds from a stream from carbonylation of methanol.

28 cl, 2 dwg

 

BACKGROUND of INVENTION

The scope of the invention

This invention relates to an improved method of removal of reducing the permanganate compounds and alkylated formed at carbonyliron methanol in the presence of a carbonylation catalyst with metals of group VIII. More specifically this invention relates to an improved method of reducing and/or removing predecessors reducing the permanganate compounds and alkylation of interim flows during the formation of acetic acid as mentioned above carbonylation.

Technical background

Among the currently used methods for the synthesis of acetic acid one of the most widely used in industry is the catalytic carbonylation of methanol with carbon monoxide, as described in U.S. patent 3.769.329 issued Paulik et al. October 30, 1973. The carbonylation catalyst contains rhodium, or dissolved or otherwise dispersed in a liquid reaction medium, or supported on an inert solid carrier, together with a halogenated promoter, an example of which is mutilated. Rhodium can be introduced into the reaction system in any of many forms, and the exact structure of the rhodium parts inside the active catalytic complex is netserve is Noah. Is not critical and the nature of the halide promoter. The patents describe a very large number of suitable promoters, most of which are organic iodides. Most typically and conveniently the reaction is carried out by continuous bubbling gaseous carbon monoxide through the liquid reaction medium in which is dissolved catalyst.

The improvement of the methods of the prior art carbonylation of alcohol to carboxylic acid having one carbon atom more than the alcohol, in the presence of a rhodium catalyst described in the public U.S. patents 5.001.259 dated March 19, 1991, 5.026.908 from 25 June 1991 and 5.144.068 from 1 September 1992 and in the European patent EP 0.161.874 B2 from 1 July 1992. As described herein, acetic acid is produced from methanol in a reaction medium containing acetate, methylguanosine, especially methyliodide, and rhodium present in a catalytically effective concentration. These patents report that the stability of the catalyst and the performance of the reactor can be maintained at unexpectedly high levels even at very low concentrations in water, i.e. a 4% wt. or less, in the reaction environment (contrary to the usual industry practice is to maintain approximately 14-15% of water) maintaining in the reaction medium, along with a catalytically active amount of rhodium and IU is greater as final concentration water concentration Yudenich ions in addition to the content of iodide, which is present in the form of methyliodide or other organic iodide. Ideny ion is present as a simple salt, and lithium iodide is preferred. The patents indicate that the concentration of acetate and Yudenich salts are important parameters that affect the rate of carbonylation of methanol to obtain acetic acid, particularly at low concentrations of water in the reactor. Using relatively high concentrations of acetate and iodide salt, receive unexpected stability of the catalyst and the performance of the reactor, even when the liquid reaction medium contains water in concentrations as low as about 0.1 wt.%, and they generally can be defined simply as "final concentration" of water. In addition, the reaction medium improves the stability of the rhodium catalyst, i.e. resistance to his deposition, especially during the stages of product recovery. At these stages of distillation in order to extract the commodity acetic acid is able to remove from the catalyst, the carbon monoxide, which in an environment that is supported in the reactor, is a ligand with a stabilizing effect on the rhodium. U.S. patents 5.001.259, 5.026.908 and 5.144.068 put into this document by reference.

It was found that although the method of carbonylation with low water content for which Holocene acetic acid reduces the formation of such by-products, as carbon dioxide, hydrogen and propionic acid, the amount of other impurities, presents, usually in trace quantities, is increased, and the quality of acetic acid was sometimes worse when attempts have been made to improve the performance improvement of the catalyst or by changing the reaction conditions.

These trace impurities adversely affect the quality of acetic acid, especially when they recycle. Impurities, which reduce the permanganate time of the sample of acetic acid include carbonyl compounds, unsaturated carbonyl compounds. The term "carbonyl"as used here is intended to denote compounds which contain aldehyde or ketone functional group, such compounds may or may not be unsaturation (seeCatalysis of Organic Reactions, 75, 369-380 (1998) for a detailed discussion of the impurities in the carbonyl process).

The present invention is aimed at reducing and/or removing reducing the permanganate compounds (CHD), such as acetaldehyde, acetone, methyl ethyl ketone, butyric aldehyde, 2-atolkachova aldehyde and 2-ethylmalonic aldehyde, etc. and the products of aldol condensation. The present invention also leads to a decrease in the content of propionic acid.

Carbonyl impurities described above, such as acetaldehyde is, can react with codename promoters of the catalyst, forming mnogoplodnye alkylidene, such as ethyliodide, propyliodide, mutilated, pentolite, hexalite etc. it is Desirable to remove alkilinity from the reaction product, because even small amounts of these impurities in the product acetic acid is able to poison the catalyst used in the preparation of vinyl acetate - product, the most widely produced from acetic acid. The present invention thus also aimed at removing alkylation, in particular alkylidene connections2-12. Accordingly, since many impurities derived from acetaldehyde, the main goal is to remove acetaldehyde from the process to reduce the content of alkylation.

Conventional methods of removing impurities include the handling of acetic acid oxidants, ozone, water, methanol, activated carbon, amines and the like, which processing may or may not be combined with the distillation of acetic acid. The most typical treatment for cleaning includes a number of distillations of the final product. It is also known, for example from U.S. patent 5.783.731, removing carbonyl impurities from organic streams by processing organic threads aminovymi compounds such as hydroxylamine, which react with carbonyl compounds is in forming oximes, followed by distillation to separate the purified organic product from the reaction products of the oxime. However, additional processing of the final product increases the cost method and the distillation of the treated commodity acetic acid can result in the formation of additional impurities.

At the same time, it is possible to obtain acetic acid of relatively high purity, commercial acetic acid, by the method of carbonylation with low water content, and the above described cleaning method often does not meet the requirements permanganate samples due to the presence of small fractions of residual impurities. Since the exposure time permanganate samples is an important industrial challenge, which must comply with trademark acid to be suitable for many applications, the presence of impurities, which reduce the permanganate time of the sample, is harmful. In addition, the removal of small amounts of these impurities from acetic acid by distillation is uneconomical or industrial unworkable as some impurities have a boiling point close to the boiling temperature of acetic acid.

Thus it becomes important to find cost-effective ways to remove impurities in any place of the way carbonylation without pollution to echnolo product or adding unnecessary costs. U.S. patent 5.756.836 specified by reference, describes a method of obtaining acetic acid of high purity by setting the concentration of acetaldehyde reaction solution below 1500 hours/million Claimed that, by maintaining the concentration of acetaldehyde below this threshold, it is possible to suppress the formation of impurities so that for acetic acid of high purity will only require distillation of crude acetic acid.

European patent EP 0 487 284 B1, published April 12, 1995, indicates that the carbonyl impurities which are present in the product acetic acid, as a rule, are concentrated in distillate columns of light fractions. Accordingly, the distillate of the column of light fractions treated with amine compound (such as hydroxylamine), which reacts with carbonyl compounds to form oxime derivatives that can be separated from the remainder of the distillate by distillation, resulting in a commodity acetic acid with improved permanganate time test.

European patent application EP 0 687 662 A2 and U.S. patent 5.625.095 describe the method of obtaining acetic acid of high purity, which stated that in the reactor, maintain the concentration of acetaldehyde 400 h/m or below, using one - or multistage distillation process for removal of acetaldehyde. Streams intended for processing for which the pressure of acetaldehyde, include a light phase containing mainly water, acetic acid and methyl acetate; heavy phase containing mainly methyliodide, methyl acetate and acetic acid; flow of distillate containing mainly methyliodide and acetate; or recirculating flow that is formed by combining light and heavy phases. These sources do not specify which of the data streams have the greatest concentration of acetaldehyde.

EP 0 687 662 A2 and U.S. patent 5.625.095 describe the management of reaction conditions to control the formation of acetaldehyde in the reactor. Although it is stated that the formation of by-products, such as CROTONALDEHYDE, 2-atolkachova aldehyde and alkylated decreases when controlling the formation of acetaldehyde, indicated that the control of the reaction conditions, as it is proposed, increases the formation of propionic acid is an undesirable by-product.

Later transferred to the total use of U.S. patents 6.143.930 and 6.339.171 indicated that it is possible to significantly reduce unwanted impurities in the product acetic acid by carrying out multi-step cleaning of distillation column of light fractions. These patents describe the cleaning process, in which the distillation column of light fractions twice distil, selecting in each case acetaldehyde distillate and returning rich metallogenetic in the reactor. Rich in acetaldehyde the optional distillate is extracted with water to remove most of acetaldehyde to reset, leaving a much lower concentration of acetaldehyde in the raffinate, which is returned to the cycle in the reactor. U.S. patents 6.143.930 and 6.339.171 introduced by this reference in their entirety.

Although the above methods have been successful in removing carbonyl impurities from the system carbonylation and largely in control of the concentrations of acetaldehyde and problems with the permanganate time of the sample in the product acetic acid, additional improvements can still be made. Accordingly, there remains a need for alternative ways to improve the efficiency of removal of acetaldehyde. The present invention offers such an alternative.

The invention

In one aspect the present invention provides a method of obtaining acetic acid, which comprises the following stages:

(a) reaction of methanol, methyl acetate, methylformate or dimethyl ether with carbon monoxide in a suitable reaction medium, which includes a catalyst and an organic iodide;

(b) separation of the reaction products on the phase of the volatile products, which contains acetic acid, methyliodide, water and reducing the permanganate compounds (UPU), and less volatile F. the memory, containing the catalyst and acetic acid;

(c) the distillation phase of the volatile products to obtain the pure product and the first distillate, which contains organic iodide, water, acetic acid and unreacted methanol;

(d) distilling at least a portion of the first distillate to obtain a second distillate containing methyliodide, water, alkylated2-12EPS and dimethyl ether;

(e) ekstraktsiyu second distillate with water to obtain a first aqueous extract and a first raffinate;

(f) extraction of the first raffinate water to produce a second raffinate and a second aqueous extract, containing concentrated UPU removal. Preferably at least a portion of the second raffinate recycle directly or not directly in the reactor and distillation products from the distillation stages.

Most preferably the second distillate contains enough of dimethyl ether in order to lower the solubility of methyliodide in water extracts, as will be explained in detail below.

In another aspect the present invention provides an improved method of separating a mixture containing water, acetic acid, methyliodide, methyl acetate, methanol, at least one alkylated2-12and at least one reducing permanganate Union (UPU). The improved method includes the et following stages: (a) distillation of the mixture for the formation of enriched UPU distillate stream, containing dimethyl ether; (b) extraction of the distillate stream water and separation of the first aqueous stream containing at least one CHD; and (c) extraction of the extracted distillate stream water and separation from his second aqueous stream containing at least one EPS. Most preferably, the distillate stream contains enough of dimethyl ether in order to lower the solubility of methyliodide in water extracts.

In another aspect the present invention provides an improved method of reducing and/or removing reducing the permanganate compounds (UPU) and (C2-12alkylidene compounds produced during carbonyliron able to this such substances as methanol, methyl acetate or dimethyl ether in the product acetic acid. By the improved method methanol carbonyliron in the reaction medium containing the catalyst and an organic iodide; the reaction products of the carbonylation is subjected to separation of the phases (1) volatile phase containing the trademarks of acetic acid, an organic iodide, water and at least one CHD, and (2) less volatile phase; and volatile phase distil, receiving the purified product and the distillate containing organic iodide, water, acetic acid and CHD. The improvement includes a stage (a) distillation at measures the part of the distillate to obtain enriched UPU distillate stream, containing dimethyl ether; (b) extraction of enriched UPU distillate stream water and separating from a stream of waste water containing EPS; and (c) extraction extracted distillate flow of water and separation of the second stream of waste water containing at least one EPS. Most preferably, the distillate stream contains enough of dimethyl ether in order to lower the solubility of methyliodide in water extracts.

Brief description of drawings

Figure 1 shows how the prototype, as described in U.S. patent 6.339.171 to remove carbonyl impurities from the intermediate flow method carbonylation for acetic acid by carbonylation reaction.

Figure 2 shows a preferred implementation of the present invention.

Although the invention permits of various modifications and alternative forms, specific implementation shown examples on circuits and will be described in detail here. It should be clear, however, that the invention is not proposed to limit the described specific forms. On the contrary, it is assumed that the invention includes all modifications, equivalents, and modifications that fall within the scope of the invention as defined in the attached claims.

Description of illustrative implementations

Explaining osushestvlyaetsya described below. In the interest of clarity, not all the characteristic features of the actual implementation are described in this description of the invention. Must be, of course, it is clear that the development of any such actual implementation should be adopted numerous specific solutions to achieve specific goals, such as compliance with the technical and economic constraints, which will vary from one implementation to another. In addition, it should be clear that such development effort might be complex and require time-consuming, but would nevertheless routine for professionals that take advantage of this description.

The purification method of the present invention is applicable to any process used for carbonylation of methanol (or other permit carbonylation agents, such as methyl acetate, methylformate or dimethyl ether, or mixtures thereof) in acetic acid in the presence of catalysts of metals of group VIII, such as rhodium and iodide promoter. A particularly suitable method is catalyzed by a rhodium carbonylation of methanol to acetic acid with low water content, an example of which is shown in U.S. patent 5.001.259. It is usually assumed that the rhodium component of the catalyst system is present in the form coordination compounds of rhodium with halogenated soy is inanam, representing at least one of the ligands of such coordination compounds. It is also believed that in addition to the coordination of rhodium and halogen with rhodium also coordinates the carbon monoxide. The rhodium component of the catalyst system can be provided by entering into the reaction zone of rhodium in the form of metallic rhodium, rhodium salts, such as oxides, acetates, iodides, etc. or other coordination compounds of rhodium, etc.

Halogen promoting component catalytic system consists of halogenated compounds, including organic halide. So, there can be used alkyl-, aryl - substituted alkyl - or aryl halides. Preferably the halide promoter is present in the form of alkylhalogenide, in which the alkyl radical corresponds to the alkyl radical of the source of alcohol, which carbonyliron. So, when carbonyliron methanol in acetic acid halide promoter should include methylguanosine and, more preferably, methyliodide.

Apply the liquid reaction medium may include any solvent compatible with the catalyst system, and may include pure alcohol or alcohol mixture of the raw material and the target carboxylic acids and/or esters of these two compounds. The preferred solvent and liquid reaction medium for the method carbonyliron the project with a low water content is a commodity carboxylic acid. So, when carbonyliron of methanol to acetic acid is the preferred solvent is acetic acid.

Water contained in the reaction medium, but at concentrations much lower than those previously considered practical to achieve a sufficient reaction rate. Previously believed that when catalyzed by rhodium carbonylation reactions of the type presented in this invention, the addition of water has had a beneficial effect on the reaction rate (U.S. patent 3.769.329). So, most of the industrial processes carried out at concentrations in water of at least about 14 wt.%. Accordingly, it was completely unexpected that the reaction rate almost equal to or greater than the rate of reaction obtained at such high water concentrations can be achieved at water concentrations below 14% and as low as about 0.1% wt.

In accordance with the method carbonyl most used for acetic acid, according to the present invention, the desired reaction rate even at low water concentrations by inclusion in the reaction environment acetate and an additional iodide ion, in excess of iodide, which is present as a promoter and a catalyst, such as methyliodide or other organic iodide. Additional ideny promoter represents th didou salt, moreover, the lithium iodide is preferred. It was found that at low concentrations in water methyl acetate and lithium iodide act as promoters only when present in relatively high concentrations, and that the promotion is higher when both of these components are present simultaneously (U.S. patent 5.001.259). It is believed that the concentration of the used lithium iodide in the reaction environment preferred system carbonylation reaction must be sufficiently high compared to the small, which was the case in the prior art with the use of halide salts in the reaction systems of this kind. The absolute concentration of iodide ion is not a limitation of the use of the present invention.

The carbonylation reaction of methanol in the product acetic acid can be carried out by contacting the methanol feedstock is in the liquid phase, with gaseous carbon monoxide, barotraumas through the liquid reaction medium with the solvent acetic acid containing rhodium catalyst and metallogeny promoter, methyl acetate and additional iodine salt, under conditions of temperature and pressure suitable for the formation of the product of the carbonylation. It should be recognized that the important is the concentration of iodide ion, and not the cation associated the iodide, and that at a given molar concentration of iodide nature of the cation is not as significant as the effect of the concentration of iodide. Any iodide salt of a metal iodide or any salt of any organic cation or Quaternary cation such as a Quaternary amine or Quaternary phosphine, or inorganic cation may be used, provided that the salt is sufficiently soluble in the reaction medium in order to provide the desired concentration of iodide. When iodide is added in the form of a metal salt, preferably it is iodide salt of the group consisting of metals of group IA and group IIA of the periodic table, as it is presented in the "Handbook of Chemistry and Physics"published by CRC Press, Cleveland, Ohio, 2002-03 (83d Edition). In particular, use of the iodides of alkali metals, preferably is lithium iodide. In the method of carbonylation with low water content, the most used in the present invention, the catalyst solution is an additional iodide excess organic iodide promoter in amounts from about 2 to about 20 wt.%, the acetate is present in amounts from about 0.5 to about 30 wt.%. and lithium iodide is present in amounts from about 5 to about 20% wt. The rhodium catalyst is present in amounts from about 200 to about 2000 parts per Milli is n (h/m).

The typical temperature of the carbonylation should be from about 150 to about 250°C, and temperature range from about 180 to about 220°C. is preferred. The partial pressure of carbon monoxide in the reactor can vary widely, but typically is from about 2 to about 30 atmospheres and preferably from about 3 to about 10 atmospheres. Thanks to the partial pressure of by-products and pressure of the contained fluid total pressure in the reactor will be in the range from about 15 to about 40 atmospheres.

A typical system response and extraction of acetic acid, which is used to promote iodide catalyzed by rhodium carbonylation of methanol to acetic acid, shown in figure 1 and comprises a liquid-phase carbonylation reactor, the apparatus a single evaporation and column of light fractions of methyliodide and acetic acid 14, which has a side stream of acetic acid 17, which is sent for further purification. The reactor and the apparatus once evaporation is not shown in figure 1. They are treated as standard equipment, well known at the present time in the technique of the carbonyl process. The carbonylation reactor is usually a or apparatus with stirrer, or a bubble column type, in which the reaction is ionic liquid or suspension is automatically maintained at a constant level. In this reactor are continuously input streams of fresh methanol, carbon monoxide, sufficient quantities of water, which is necessary in order to maintain at least a finite concentration of water in the reaction medium, recycle catalyst solution from a cube of unit single evaporation cycle phase methyliodide and acetate and recycle water explicilty phase of the receiver-decanter of distillate columns of light fractions of methyliodide-acetic acid or column-stabilizer 14. Apply distillation systems, which are used to extract the crude acetic acid and recycling the catalyst solution, methyliodide and acetate in the reactor. In a preferred method, the carbon monoxide is continuously introduced into the carbonylation reactor directly below the mixer used for mixing the contents. Gaseous food thoroughly dispersed in the reaction liquid of this mixing device. The flow of the gas stavki release from the reactor to prevent the accumulation of gaseous by-products and maintain a specified partial pressure of carbon monoxide at a given total pressure of the reactor. The temperature of the reactor regulate and carbon monoxide is injected at a rate sufficient to maintain the desired total pressure of the reactor.

The Jew is the second product is withdrawn from the carbonylation reactor with speed, sufficient to maintain a constant level, and injected into the apparatus a single evaporation. From the apparatus a single evaporation of the catalyst solution is removed (mainly acetic acid containing rhodium and jodido salt together with lower amounts of acetate, methyliodide and water), while the flow of steam distillation contains almost entirely trademarks of acetic acid together with methyliodide, acetate and water. Dissolved gases leaving the reactor and supplied to the device a single evaporation, consists of a portion of the carbon monoxide together with gaseous byproducts, such as methane, hydrogen and carbon dioxide, and out of the apparatus a single evaporation as part taken from the top of the thread. Select top stream is directed into the column of light fractions or stabilizer as stream 26.

In U.S. patent 6.143.930 and 6.339.171 described that the concentration of EPS and, in particular, acetaldehyde in the light phase is about 3 times higher than in the flow of heavy phase leaving the column 14. Thus, in accordance with the present invention the stream 28 containing the UPU is sent to distillation column 18.

The present invention can in General be regarded as an improved way of distillation, UPU, mainly acetaldehyde and alkylation from the vapor phase takoh the flow of acetic acid, as the distillate of the column of light fractions or combination of columns of light fractions/drying. The flow of the vapor phase is subjected to distillation and then twice extracted to remove the UPU. A particularly preferred method of removing acetaldehyde and alkylation from the flow of the first vapor phase acetic acid and lower concentrations of propionic acid in the product includes the following stages:

(a) condensation of flow of the first vapor phase acetic acid in the first capacitor and two-phase separation for formation of the first product of the heavy liquid phase and the first light liquid phase;

(b) a first distillation product of the heavy liquid phase in a first distillation column for the education stream of the second vapor phase trademarks of acetic acid, which is enriched with aldehydes and alkylidene compared with the specified flow of the first vapor phase acetic acid;

(c) condensation of flow of the second vapor phase in the second capacitor to form the product of the second liquid phase;

(d) distillation of the product of the second liquid phase in the second distillation column to form a stream of the third vapor phase;

(e) condensation of flow of the third vapor phase and extraction of the condensed stream with water to remove residual acetaldehyde; and

(f) extraction of the extracted condensed p the current water for additional removal of residual acetaldehyde.

The implementation of the method according to the prototype, which is disclosed in U.S. patent 6.339.171 shown in figure 1. Referring to figure 1, the flow of the first vapor phase acetic acid (28) contains methyliodide, methyl acetate, acetaldehyde and other carbonyl components. This stream is then condensed and separated (unit 6) for separating heavy product phase containing a large proportion of the catalytic components, which recycle to the reactor (not shown in Fig.1)and light phase (30)containing acetaldehyde, water, and acetic acid.

Any phase of the light distillate fractions may then be subjected to distillation to remove from the stream of EPS and, mainly acetaldehyde component, although it is preferable to remove the UPU of the light phase (30), since it was found that the concentration of acetaldehyde in this phase is slightly higher. In the implementation shown and described herein, the distillation is carried out in two stages, but it should be clear that the distillation can also be carried out in the same column. Light phase (30) is sent to the column (18), which is used for formation of the second vapor phase (36), enriched aldehyde and alkylidene against the stream 28. Thread 36 condense (device 20) to form the product of the second liquid phase. The second liquid phase (40)containing acetaldehyde, methyliodide, methanol and methyl acetate, send the second di tillation column (22), where acetaldehyde is separated from the other components. It was found that the method according to the invention reduces and/or removes at least 50% alkylidene impurities detected in the stream of acetic acid. It was also shown that acetaldehyde and its derivatives are reduced and/or removed at least 50%, most often more than 60%. In the result, it is possible to keep the concentration of propionic acid in the product acetic acid below about 400 ppm (wt.), preferably below about 250 parts per million.

Vapors removed from the top of the column of light fractions or column-stabilizer 14, line 28, condensed and sent to the device 16. Vapors are cooled to a temperature sufficient to condense and separate the condensed methyliodide, methyl acetate, acetaldehyde and other carbonyl components and water into two phases. Part of the flow 28 includes noncondensable gases such as carbon dioxide, hydrogen and the like, and may be removed in the Stripping, as shown by flow 29 in figure 1. From the receiver the decanter of distillate 16 deduce also that is not shown in figure 1, the heavy phase stream 28. Usually this heavy phase is returned to the cycle in the reactor, but the outlet stream, usually a small amount, for example, 25% vol., preferably less than about 20% vol., heavy phase can also be sent to the pererabotka CARBONYLS, and the remainder returned to the cycle in the reactor or reaction system. This bypass flow of heavy phase can be recycled separately or in combination with a light phase (stream 30) for further distillation and extraction of carbonyl impurities.

Light phase (stream 30) is sent to a distillation column 18. Part of the stream 30 is directed back into the column of light fractions 14 as stream irrigation 34. The remainder of the stream 30 is fed to the column 18 as stream 32, approximately in the middle of the column. Column 18 is used for concentration of the aldehyde flow components 32 in the distillate stream 36 Department of water and acetic acid from the lighter components. The first distillation column 18 preferably contains approximately 40 plates, and the temperature varies from about 283°F (139,4°C) in the cube to about 191°F (88,3°C) in the top of the column. From the cube column 18 output stream 38 containing about 70% water and 30% acetic acid. Stream 38 is processed, usually cooled using a heat exchanger and returned to the cycle in the decanter 16 distillate columns of light fractions through the threads 46, 48 and, finally, into the reactor or reaction system. It was found that the recycling stream 38, indicated as stream 46 through the decanter 16 increases the efficiency of the process according to the invention and allows for a larger amount of acetaldehyde present in egcoa phase, thread 32. It was found that the thread 36 has a content of acetaldehyde is approximately seven times greater when the thread 38 recycle through the decanter 16 so. From the top of column 18 output stream 36 containing EPS and, in particular, acetaldehyde, methyliodide, methyl acetate and methanol, and alkilinity. Stream 36 is then sent to the receiver distillate 20 after it has cooled for condensation of all present condensed gases.

From the receiver distillate 20 output stream 40 containing acetaldehyde, methyliodide, methyl acetate and methanol. Part of the flow 40 return to the column 18 as a stream of irrigation 42. The remainder of the stream 40 is fed to the second distillation column 22 is close to the cube of the column. Column 22 serves to separate the greater part of acetaldehyde from methyliodide, methyl acetate and methanol in stream 40. In one implementation of the column 22 contains about 100 plates and operates at temperatures in the range of from about 224°F (106,6°C) in the cube to about 175°F (79,4°C) in the top of the column. In an alternative preferred implementation of the column 22 contains an attachment instead of plates. The preferred nozzle is arranged nozzle with interfacial surface about

65 ft2/ft3preferably made of metal alloy, such 2205, or other supplementary material, provided h is about it is compatible with compositions, must be cleaned in the column. During the experiments it was found that uniform loading of the column, which is required for good separation was better with a streamlined nozzle than with plates. An alternative can be applied ceramic nozzle. The remainder of the column 22, the thread 44 is removed from the cube of the column and returned to the carbonylation cycle.

Acetaldehyde is polymerized in the presence of methyliodide, forming metaldehyde and paraldehyde is recommended. These polymers generally have a low molecular weight lower than about 200. It was found that the paraldehyde is recommended is relatively soluble in the reaction liquid and, mainly, in acetic acid. Metaldehyde after its precipitation represents Pechorsky granular polymer that is not soluble in the reaction liquid in excess of a concentration of about 3% wt.

However, as described in U.S. patent 6.339.171, it was found that during the reaction, and when heated in the column 22 are formed polymers of acetaldehyde higher molecular weight. It is believed that these polymers of higher molecular weight (molecular weight greater than about 1000) are formed during processing of the light phase and are viscous and thixotropic. When the system is warm, they tend to harden and stick to the walls of the column, where their removal I have is heavy. After polymerization, they are only poorly soluble in organic or aqueous solvents and can be removed only by mechanical means. Thus, the required inhibitor, preferably in the column 22 to reduce the formation of these impurities, i.e. metaldehyde and paraldehyde is recommended and polymers of acetaldehyde higher molecular weight (ASN). The inhibitor usually consists of alkanols With1-10preferably, methanol, water, acetic acid and the like used individually or in combination with each other or with one or more other inhibitors. Stream 46, which is part of the rest of the columns 18 and outlet stream 38 contains water and acetic acid and, therefore, may serve as an inhibitor. As shown in figure 1, the thread 46 is divided, forming the threads 48 and 50. Stream 50 is added to the column 22 to inhibit the formation of impurities metaldehyde and paraldehyde is recommended and polymers of higher molecular weight. Since the remainder of the second column 22 are returned to the cycle in the reactor, any added inhibitors should be compatible with the chemistry of the reactor. It was found that small amounts of water, methanol, acetic acid or their combinations do not disturb the chemistry of the reactor and virtually eliminates the formation of polymers of acetaldehyde. Stream 50 is also preferably used as the inhibitor, PQS is lku this substance do not change the water balance of the reactor. Although the water is particularly preferred as an inhibitor, other important advantages are achieved with the addition of water to the column 22, as will be explained below.

From the top of the column 22 extends stream 52 containing the UPU. Stream 52 is sent to the condenser and then to the receiver distillate 24. After condensation of all non-condensable substances are output in the form of gas from the receiver 24; condensed matter out of the receiver 24 in the form of a stream 54. Stream 56, the discharge stream 54, is used as the irrigation of the column 22. From the cube column 22 extends stream 44 containing methyliodide, methanol, methyl acetate, methanol and water. This stream is combined with a stream 72, which will be described below, and sent to the reactor.

For the mechanism of extraction is important that the distillate stream of the column 22 remained cold, usually at a temperature of about 13°C. This stream may be obtained or maintained at a temperature of about 13°C conventional methods known in the art, or by any method usually adopted in the industry.

Thread 58 after exiting the reactor is preferably passed through a condenser/cooler (now thread 62) and then sent to the first extractor 27. In the extractor 27 EPS and alkylated extracted with water, preferably water from the underlying stream, so as to maintain the balance of water in the reaction system.

The result of this is th extraction methyliodide separated from the aqueous phase of the UPU and alkylation. In the preferred implementation used a mixer-settler with respect to water:power for approximately 2.

The flow of aqueous extract of 64 leaves the extractor 27 with its top. This rich EPS and, in particular, is rich in acetaldehyde aqueous phase is sent for recycling. From the extractor also deduce refinity stream 66 containing methyliodide.

Refinity stream 66 is extracted with additional water in the second reactor 25. In the extractor 25, as in the extractor 27, EPS and alkylated extracted with water, preferably water from the internal thread so as to maintain the balance of water in the reaction system. The result of this extraction, methyliodide is separated from the aqueous phase of the UPU and alkylation. In the preferred implementation used a mixer-settler with respect to water:power for approximately 1. The flow of aqueous extract 70 is removed from the extractor 25 from the top. This rich EPS and, in particular, is rich in acetaldehyde aqueous phase is sent for recycling. From the extractor also deduce refinity stream 72 containing methyliodide. This thread is usually returned to the cycle in the reactor system and ultimately into the reactor.

An ordinary person skilled in the art should be immediately clear that the additional degree of extraction can be added, if required, in order to further increase the proportion of methyl who Oded Hagai, retrieved from rich acetaldehyde distillate of the column 22. It should be also clear that additional variations, in which a water stream passes through successive stages of extraction, and not using fresh water at each step. Finally, it should be clear that a multi-stage extraction, which is described here can be carried out in attachment extractor (continuous contact)with an appropriate number of theoretical stages instead of having discrete steps.

Potential difficulties described here above multistage extraction is that each water extraction removes not only acetaldehyde, but also a measurable quantity of methyliodide. As explained here above, since methyliodide is a particularly expensive component of the reaction system, it is highly desirable to minimize the number of methyliodide, which is removed from the way the waste to reduce the amount of fresh methyliodide, which must be filed in the reactor. Applicants have discovered, however, that the addition of dimethyl ether (DME) to the power extractor 27 limits the loss of methyliodide stages of extraction. The presence of DME lowers the solubility of methyliodide in the water, thereby reducing the number of methyliodide extractable in aqueous extract on the Oka 64 and 70 and lost during the treatment of waste water. As an example, applicants have observed that the concentration of methyliodide in stream 64 fell from approximately 1.8%, when DME was not present, up to about 0.5%, when DME was present. Accordingly, another aspect of the present invention includes a step of injection of DME in the process stream before the extractor 27, such as stream 62, to reduce the loss of methyliodide in aqueous extract streams 64 and 70. The required amount of DME in the stream 62 can be achieved by adding water to the column 22, for example in food 40 or irrigation of the column 50. Although there is no need in understanding the exact mechanism for the formation of DME in the column 22 for the implementation of the present invention, it is believed that this water reacts with the acetate and/or methyliodide in the column 22, to form methanol, which is then dehydratases in the presence of an acid catalyst (such as HI), forming DME. All DME, which were not extracted in the aqueous extract streams 64 and 70, is recycled directly or not directly in the reaction system, where it reacts with carbon monoxide and water to form acetic acid.

Although the invention has been described with reference to the preferred embodiment, obvious modifications and changes can be made by specialists in related fields. In particular, although the present invention has been generally described above using the phase Les is such fractions of the column 14, any thread of the carbonyl process, having a high concentration of EPS and alkylation, can be processed in accordance with the present invention. Therefore, it is assumed that the invention includes the full extent of all such modifications and changes that are included in the scope of the following claims or the equivalents.

1. An improved method of reducing and/or removing reducing the permanganate compounds (UPU), carboxylic acids With3-8and C2-12alkylidene compounds produced during carbonyliron able to carbonyliron reagent selected from the group consisting of methanol, methyl acetate, methylformate, dimethyl ether and mixtures thereof, in the product acetic acid, in which the products specified carbonylation include volatile phase, which is distilled, receiving cleared commodity acetic acid and a first distillate comprising methyliodide, water and at least one UPU,
where the improvement involves the following stages:
(a) the division received the first distillate to light and heavy phase, followed by distillation at least part of the light phase to obtain a second distillate stream comprising methyliodide, dimethyl ether and the specified at least one of the UPU, which is sent to the next stage of distillation, where as distillate the image of the fast stream, containing the UPU;
(b) adding dimethyl ether in the power of the specified stream containing EPS, and extraction of the flow of water for the formation of the first raffinate and a first aqueous extract stream containing the specified at least one EPS; and
(C) extraction of the first raffinate water for the formation of the second raffinate and a second aqueous extract stream containing the specified at least one EPS.

2. The method according to claim 1, wherein the specified at least one EPS includes acetaldehyde.

3. The method according to claim 2, in which the specified volatile phase removes a sufficient amount of acetaldehyde to support specified in the purified product of the concentration of propionic acid below about 400 hours/mn (wt.)

4. The method according to claim 2, in which the specified volatile phase removes a sufficient amount of acetaldehyde to support specified in the purified product of the concentration of propionic acid below about 250 hours/mn (wt.)

5. The method according to claim 1, in which the improvement further includes entering at least part of the second raffinate directly or not directly in the reaction medium.

6. The method according to claim 1, wherein the extraction step (b) and (C) carried out in a separate apparatus.

7. The method according to claim 1, wherein the extraction step (b) and (C) is carried out in at least one extractor with a layer of the density of the I.

8. The method according to claim 1, wherein said first distillate comprises dimethyl ether.

9. The method according to claim 1, further comprising a stage of adding dimethyl ether to at least one stream associated with the specified stage distillation (a).

10. The method according to claim 1, in which the specified stage distillation (a) additionally includes the stage of formation of dimethyl ether during the distillation.

11. The method of obtaining acetic acid, comprising the steps:
(a) carbonylation of at least one reagent selected from the group consisting of methanol, methyl acetate, methylformate and dimethyl ether in a reactor containing a reaction medium comprising an organic iodide;
(b) separation of the products specified carbonylation phase volatile product comprising acetic acid, water and at least one reducing permanganate Union (UPU), and less volatile phase;
(c) distilling the specified phase volatile product to obtain a purified trademarks of acetic acid and a first distillate comprising the specified organic iodide, water and at least one reducing permanganate Union (UPU);
(d) separating the received first distillate to light and heavy phase followed by distillation at least part of the light phase to obtain enriched EPS of the second distillate, which is ATEM sent to the next stage of distillation, where as distillate produces a stream containing the UPU; and
(e) adding dimethyl ether in the power extractor for extract stream containing the UPU water where the stream containing the UPU, additionally includes dimethyl ether; and extraction of the flow containing the UPU water, where stage (e) includes at least two successive stages of extraction, with each stage extraction comprises contacting a stream containing the UPU, with water and separation of the water flow, including the specified at least one EPS.

12. The method according to claim 11, in which indicated at least one EPS includes acetaldehyde.

13. The method according to item 12, which fly from the specified phase removes a sufficient amount of acetaldehyde to support specified in the purified product of the concentration of propionic acid below about 400 hours/mn (wt.)

14. The method according to item 12, which fly from the specified phase removes a sufficient amount of acetaldehyde to support specified in the purified product of the concentration of propionic acid below about 250 hours/mn (wt.)

15. The method according to claim 11, further comprising recycling at least part of the extracted second distillate directly or not directly in the reactor.

16. The method according to claim 11, in which at least two stages of extraction is carried out in ordelryappefe.

17. The method according to claim 11, in which at least two stages of extraction is carried out in at least one extractor with packing layer.

18. The method according to claim 11, wherein said second distillate includes the amount of dimethyl ether effective to reduce the solubility of methyliodide in at least one of said aqueous extract streams.

19. The method according to claim 11, wherein said first distillate comprises dimethyl ether.

20. The method according to claim 11, further comprising the stage of adding dimethyl ether to at least one stream associated with the specified stage distillation (d).

21. The method according to claim 11, in which the specified stage distillation (d) additionally includes the stage of formation of dimethyl ether during the distillation.

22. The method of separating a mixture comprising water, acetic acid, methyliodide, methyl acetate, methanol and at least one reducing permanganate Union (UPU), obtained by separation of the phases, the liquid-vapor outlet stream of the reactor carbonylation of methanol for the formation of a vapor phase and a liquid phase, distilling the vapor phase to liquid product comprising acetic acid and a first distillate, condensing at least part of the first distillation, to form a liquid composition comprising methyl acetate, methyliodide, water, methanol and at least one is regenerating permanganate Union (UPU), the separation of the liquid composition on the light and heavy phase comprising methyliodide, where the light phase is a specified mixture, where the method involves the following stages:
(a) distilling the mixture to obtain a second distillate stream comprising at least one reducing permanganate Union (UPU)which is sent to the next stage of distillation, where as distillate produces a stream containing EPS and dimethyl ether; and
(b) extraction of enriched UPU flow of water,
where stage (b) comprises at least two successive stages of extraction, where each stage extraction comprises contacting the enriched UPU flow of water and the separation from it of the water flow, including the specified at least one CHD, where dimethyl ether is added to the specified enriched UPU distillate stream before extraction enriched UPU flow of water.

23. The method according to item 22, wherein said enriched UPU distillate stream includes the amount of dimethyl ether effective to reduce the solubility of methyliodide in the water extraction threads.

24. The method according to item 22, in which indicated at least one EPS includes acetaldehyde.

25. The method according to item 22, in which the specified stage distillation (a) additionally includes the stage of education is dimetilovogo ether during the distillation.

26. The method according to p. 25, further comprising recycling at least part of the extracted enriched UPU distillation directly or not directly in the reactor.

27. The method according to item 22, which fly from the specified phase removes a sufficient amount of acetaldehyde to support specified in the purified product of the concentration of propionic acid, the following approximate 400 h/mn (wt.)

28. The method according to item 22, which fly from the specified phase removes a sufficient amount of acetaldehyde to support specified in the purified product of the concentration of propionic acid below about 250 hours/mn (wt.).



 

Same patents:

FIELD: chemistry.

SUBSTANCE: method includes carbonylation of the alcohol and/or of its reactive derivative with carbon monooxide in liquid reaction mixture carried out in carbonylation reactor. The said liquid reaction mixture contains the said alcohol and/or its reactive derivative, carbonylation catalyst, alkyl halide cocatalyst whereat the said catalyst includes at least one metal selected from rhodium or iridium coordinated with polydentate ligand whereat the said polydentate ligand has the bite angle at least 145° or forms the "hard" Rh or Ir metal-ligand complex; the said polydentate ligand includes at least two coordination groups; at least two of them independently contain P, N, As or Sb as coordination atoms. The hydrogen/carbon monooxide mole ratio is supported in the range at least 1:100 and/or carbon monooxide directed to carbonylation reactor contains at least 1 mole % of hydrogen; catalyst flexibility range is less 40°. The method is tolerable to hydrogen presence i.e. liquid side-products are formed in small amounts or are not formed at all.

EFFECT: improvement of the method of carboxylic acid and its ester obtaining.

49 cl, 3 tbl, 13 ex

FIELD: chemistry.

SUBSTANCE: proposed method involves the following stages: (a) reaction of carbon monoxide with at least one reagent chosen from a group, consisting of methanol, methyl acetate, methyl formate and dimethyl ether and their mixture in a reaction medium, containing water, methyl iodide and catalyst for obtaining the reaction product, containing acetic acid; (b) gas-liquid separation of the said reaction product to obtain a volatile phase, containing acetic acid, water and methyl iodide and a less volatile phase, containing the said catalyst; (c) distillation of the above mentioned volatile phase to obtain a purified product of acetic acid and a first overhead fraction, containing water, methylacetate and methyl iodide; (d) phase separation of the above mentioned first overhead fraction to obtain the first liquid phase, containing water, and second liquid phase, containing methyl iodide and methyl acetate; and (e) feeding dimethyl ether directly or indirectly into a decantation tank of light fractions for phase separation of the said first overhead fraction in a quantity, sufficient for increasing separation of the first overhead fraction to form the first and second liquid phases.

EFFECT: improvement of the method of producing acetic acid.

8 cl, 1 dwg

FIELD: chemistry.

SUBSTANCE: proposed is a method of oxidising alkane from C2 to C4, obtaining the corresponding alkene and carboxylic acid and/or oxidising alkene from C2 to C4, obtaining the corresponding carboxylic acid. The method involves addition into the reaction zone of the above mentioned alkane and/or alkene, containing molecular oxygen gas, carbon monoxide and optionally water, in the presence of a catalyst, effective for oxidising the alkane to the corresponding alkene and carboxylic acid and/or effective for oxidising the alkene to the corresponding carboxylic acid at temperature between 100 and 400 °C. Concentration of carbon monoxide is kept between 1 and 20% of the total volume of the initial material added to the oxidation reaction zone. The method can optionally involve further reaction in a second reaction zone.

EFFECT: new oxidation method for producing carboxylic acids and alkenes.

30 cl, 3 ex, 1 tbl, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of producing methanol, acetic acid and optionally vinyl acetate, which includes integrated stages: separation of hydrocarbons source into first and second hydrocarbons flows; vapour reforming of first hydrocarbons flow with vapour in order to obtain subjected to reforming flow; autothermal reforming of mixture of subjected to reforming flow and second hydrocarbons flow with oxygen and carbon dioxide in order to obtain synthesis-gas flow; separation of smaller part of synthesis-gas flow into flow with higher carbon dioxide content, flow with higher hydrogen content and flow with higher content of carbon oxide; recirculation of flow with higher carbon dioxide content to autothermal reforming; compression of remaining part of synthesis-gas flow, CO2 flow, not necessarily from associated process, and at least part of flow with higher hydrogen content for supplying feeding flow to circuit of methanol synthesis in order to obtain methanol product, whose stoichiometric coefficient is determined as [(H2-CO2)/(CO+CO2)], and stoichiometric coefficient of feeding flow constitutes from 2.0 to 2.1; acetic acid synthesis from at least part pf methanol product and flow with higher content of carbon oxide, and optionally synthesis of vinyl acetate from at least part of synthesised acetic acid.

EFFECT: elaboration of improved method of producing methanol, acetic acid, characterised by highly economical indices and low intensity of CO2 emission.

23 cl, 2 ex, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention concerns improved method of obtaining carboxylic acid and/or complex alcohol ether and carboxylic acid, involving carbonylation of C1-C8 aliphatic alcohol and/or its reactive derivative by carbon monoxide in liquid reaction mix in carbonylation reactor. Liquid reaction mix includes indicated alcohol and/or its reactive derivative, carbonylation catalyst, alkylhalide co-catalyst and optionally water in limited concentration, the catalyst including cobalt, rhodium or iridium coordinated with tridentate ligand, or their mix. Also invention concerns application of carbolylation catalyst including cobalt, rhodium or iridium coordinated with tridentate ligand, or their mix, in carbonylation method of obtaining carboxylic acid and/or complex alcohol ether and carboxylic acid.

EFFECT: enhanced carbonylation speed and selectivity.

36 cl, 6 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention claims method of preparation of catalytic composition applied onto a carrier and acceptable for ethane and/or ethylene oxidation to acetic acid, where catalytic composition applied onto carrier includes catalyst of one or more metal components, on a carrier with aluminium alpha-oxide. Method involves the following stages: (a) preparation of suspension of one or more metal components and aluminium alpha-oxide carrier or carrier precedent particles, (b) dispersion drying of suspension, and optionally (c) calcination of dispersion-dried suspension to obtain catalytic composition applied onto carrier. Invention also claims catalytic composition applied onto carrier and obtained by the claimed method, and method of selective ethane and/or ethylene oxidation to acetic acid using the catalytic composition applied onto carrier.

EFFECT: high selectivity of target products and reduced COX generation.

44 cl, 2 tbl, 1 dwg, 3 ex

FIELD: chemistry.

SUBSTANCE: reaction of alkene with molecular oxygen is carried out in reactor with pseudoliquefied layer in presence of catalytically active pseudoliquefied layer of solid particles, which lies in the following: gas, containing molecular oxygen, concentration of oxygen in which exceeds its concentration in air, is introduced into pseudoliquefied layer simultaneously supporting turbulent mode in pseudoliquefied layer. Invention also relates to method of obtaining vinylacetate by reaction of ethylene and acetic acid with molecular oxygen in reactor with pseudoliquefied layer in presence of catalytically active pseudoliquefied layer of solid particles, which have diameter in range from 20 to 300 mcm, distribution according to particle diameter constitutes at least 20 mcm; at to method of carrying out reaction of molecular oxygen with ethane, ethylene or their mixture obtaining acetic acid and optionally ethylene in reactor with pseudoliquefied layer in presence of catalytically active pseudoliquefied layer of solid particles.

EFFECT: elaboration of safer method of carrying out reaction.

45 cl, 2 tbl, 3 ex,4 dwg

FIELD: chemistry.

SUBSTANCE: improved is method of obtaining acetic acid by means of carbonilation of methanol and/or its reaction-able derivative with carbon monoxide in carbonilation reaction zone, which contains liquid reaction medium, including iridium carbonilation catalyst, methyliodide co-catalyst, amount of water within range from 0.1 to 20 wt %, acetic acid, methylacetate, at least one promoter - ruthenium, and stabilising compound, selected from group, which consists of alkali metal iodides, alkali-earth metal iodides, metal complexes, able to generate ions I-, salts, able to generate I-, and mixtures of two or more such compounds, molar ratio of promoter to iridium being more than 2 up to 15:1, and molar ratio of stabilising compound to iridium is within range (from more than 0 to 5):1, and where method includes additional stages: a) from said carbonilation reaction zone liquid reaction medium with dissolved and/or carried along carbon monoxide and other gases is drained; b) said drained liquid reaction medium is not obligatory passed through one or several additional reaction zones in order to convert at least part of dissolved and/or carried along carbon monoxide; c) said liquid reaction medium from stage (a) and stage (b) is passed in one or several stages of fast evaporation, in order to form (i) vapour fraction, including condensing components and waste low pressure gas, condensing components contain obtained acetic acid and waste low pressure gas, which contains carbon monoxide and other gases, dissolved and/or carried along with drained liquid reaction medium, and (ii) liquid fraction, including iridium carbonilation catalyst, promoter and acetic acid as solvent; d) from waste low pressure gas condensing components are separated; and e) liquid fraction from stage of fast evaporation is recirculated into carbonilation reactor.

EFFECT: method allows to prevent or reduce loss of catalyst and promoter.

14 cl, 7 tbl, 2 dwg, 32 ex

FIELD: chemistry.

SUBSTANCE: catalytic system for obtaining acetic acid includes iridium carbonilation catalyst, methyliodide co-catalyst, non-obligatory, at least one of the following elements: ruthenium, osmium, rhenium, zinc, gallium, tungsten, cadmium, mercury and indium, ant, at least, one promoter - non-halogenohydrogen acid. Non-halogenohydrogen acid can represent oxo-acid, superacid and/or hateropolyacid. Method of obtaining acetic acid by reaction of carbon monoxide with methanol and/or its reaction-able derivative in liquid reaction composition, which includes methylacetate, water in limited concentration, acetic acid and said catalytic system, is described. Application of catalytic system for obtaining acetic acid is described.

EFFECT: increasing rate of carbonilation.

27 cl, 5 tbl, 20 ex

FIELD: chemistry.

SUBSTANCE: invention relates to method of oxidising alkane from C2 to C4 with the obtaining of corresponding alkene and carboxylic acids. The method includes the following stages: (a) contact in the oxidation reaction zone of the alkane, which contains molecular oxygen gas, not necessarily corresponding to the alkene and not necessarily water in the presence of at least one catalyst, effective with the oxidation of the alkane to the corresponding alkene and carboxylic acid, alkane, oxygen and water; (b) separation in the first separating agent at least part of the first stream of products in a gaseous stream, which includes alkene, alkane and oxygen, and a liquid stream, which includes carboxylic acid; (c) contact of the mentioned gaseous stream with the solution of a salt of metal, capable of selectively chemically absorbing alkene, with the formation of a liquid stream rich in chemically absorbed alkene; (d) isolation from the flow of the solution of salt of the metal. The invention also relates to combined methods of obtaining alkyl-carboxylate or alkenyl-carboxylate (for example vinyl acetate), moreover these methods include oxidising of alkane from C2 to C4 with the obtaining of corresponding alkene and carboxylic acid, isolation of alkene from the mixture of alkene, alkane and oxygen by absorption using the solution of the salt of metal and extraction of the stream rich in alkene from the solution of the salt from metal for using when obtaining alkyl-carboxylate and alkenyl-carboxylate.

EFFECT: improved method of oxidising alkane from C2 to C4 with the obtaining of corresponding alkene and carboxylic acids.

46 cl, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of recovering (meth)acrolein or (meth)acrylic acid, including stage of cooling of gaseous reaction mixture containing (meth)acrolein or (meth)acrylic acid obtained by reaction of catalytic oxidation in vapour phase of one or both reagents selected from (A) propane, propylene or isobutylene and (B) (meth)acrolein, with molecular oxygen or gas, containing molecular oxygen, to temperature 140-250°C; contacting of said gaseous reaction mixture with solvent, whose temperature is 20-50°C, in recovery installation for recovering (meth)acrolein or (meth)acrylic acid in solvent, where said recovery installation contains contact zone, where gaseous reaction mixture contacts with solvent, having transversal section of round form and many devices of gaseous reaction mixture supply for supplying gaseous reaction mixture into contact zone, devices of gaseous reaction mixture supply are installed in contact zone at the same height directed towards contact zone centre, gaseous reaction mixture is supplied to contact zone from devices of gaseous reaction mixture supply and is subjected to collision straight in one point of contact zone, and recovery installation does not have device which prevents direct collision of gaseous mixture supplied from devices of gaseous reaction mixture supply. Invention also relates to recovery installation for recovering (meth)acrolein or (meth)acrylic acid.

EFFECT: ensuring efficient recovering (meth)acrolein or (meth)acrylic acid from gas containing (meth)acrolein or (meth)acrylic acid, preventing polymerisation.

7 cl, 5 dwg, 4 ex

FIELD: chemistry.

SUBSTANCE: present invention pertains to extraction of a metallic catalyst from a mother solution, obtained during synthesis of carbonic acid, usually terephthalic acid. In the first version, the method of separating metallic catalyst from a stream of mother solution involves the following stages: (a) evaporation of the mother solution, containing carbonic acid, the metallic catalyst, impurities, water and a solvent, in the zone of the first evaporator, obtaining a vapour, containing water and solvent, and concentrated mother solution; (b) evaporation of the concentrated mother solution in the zone of the second evaporator, where evaporation in the zone of the second evaporator is carried out at 150-220°C temperature, forming a stream rich in solvent and a stream of super-concentrated mother solution in molten dispersion state, where a total of 95-99 wt % of solvent and water is removed from the mother solution during evaporation stages (a) and (b); (c) mixing the water-solvent solution in the mixing zone, with super-concentrated mother solution, forming an aqueous mixture; (d) separation of organic impurities in the aqueous mixture in the separation zone of solid substance/liquid phase, forming a pure aqueous mixture; (e) addition of extraction solvent to the aqueous mixture or pure aqueous mixture in the extraction zone, forming an extract or rafinate, containing the metallic catalyst; and (f) separation of the extract and the solvent rich stream in the separation zone, forming a stream of organic impurities with high boiling point and a stream of extraction solvent. The invention has three versions.

EFFECT: extraction of expensive metallic catalyst in active form, suitable for repeated use, and acetic acid, contained in the mother solution with removal of most impurities present in the extracted stream.

20 cl, 1 tbl, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to the removal of the metallic catalyst from stock solution, obtained during the synthesis of carboxylic acids, normally terephthalic acid. Method of removing the metallic catalyst from the stream of stock solution containing carboxyl acid includes the following stages: (a) graduating the stock solution, which contains the carboxyl acid, metallic catalyst, impurities, water and solvent, in the zone of the first evaporator obtaining a stream of water vapour and a stream of concentrated stock solution; (b) evaporating of the specified stream of concentrated stock solution to the zone of the second evaporator forming a stream rich in the solvent and a stream of super-concentrated stock solution; (c) removing organic impurities from super-concentrated stock solution with the help of water-solvent solution in the zone of the separating phase of solid substance/liquid forming a stream of water and a second stream of water; (d) mixing in the zone of mixing water and not necessarily the extraction solvent with the specified water stream and the specified second water stream forming and aqueous solution; (e) adding the extraction solvent to the specified water solution in the extraction zone forming a stream of extract and a stream of raffinate containing the specified metallic catalyst; and (f) separating the specified stream of extract in the separating zone forming a stream of organic impurities with a high boiling point and a stream of the removed extraction solvent. In a different version of the realisation of the method of removing the metallic catalyst from the stream of stock solution containing the carboxylic acid includes the following stages: (a) evaporating of the stock solution containing the carboxylic acid, metallic catalyst, impurities, water and solvent, in the zone of the first evaporator obtaining a stream of water and a stream of concentrated stock solution; (b) evaporating the specified stream of concentrated stock solution in the second evaporating zone obtaining a stream rich in the solvent and stream of super-concentrated stock solution, where about 85 to about 99% mass, of the solvent and water is removed from the specified stock solution at the stage (a) and stage (b) in combination; (c) removing of organic impurities from the specified super-concentrated stock solution with help of the water-solvent solution in the zone of the separating phase of solid substance/liquid forming a stream of water and a second stream of water; where the specified water-solvent solution is introduced to the specified zone of the separating phase of solid substance/liquid at a temperature interval from about 20°C to 70°C; (d) mixing in the zone for mixing water and not necessarily the extraction solvent with the specified stream of water and the specified second water stream forming a water mixture; (e) introducing the extraction solvent to the specified water solution to the extraction zone forming a stream of extract and a stream of raffinate; and (f) separating of the specified flow of extract in the zone of separation forming a flow of organic impurities with a high boiling point and a flow of the extraction solvent removed.

EFFECT: increase in the efficiency of the method of removing impurities and working capacity of the method in comparison to the existing methods.

17 cl, 1 tbl, 1 dwg

FIELD: chemistry.

SUBSTANCE: method of obtaining product - purified carboxylic acid, includes: (a) oxidation of aromatic initial materials in primary oxidation zone with formation of raw carboxylic acid suspension; where raw carboxylic acid suspension contains terephthalic acid; where said oxidation is carried out at temperature within the range from 120°C to 200°C; (b) withdrawal of admixtures from raw suspension of carboxylic acid, removed at temperature from 140°C to 170°C from stage of oxidation of paraxylol in primary oxidation zone and containing terephthalic acid, catalyst, acetic acid and admixtures, realised in zone of solid products and liquid separation with formation of mother liquid flow and product in form of suspension; where part of said catalyst in said suspension of raw carboxylic acid is removed in said mother liquid flow; and where into said zone of solid products and liquid separation optionally additional solvent is added; (c) oxidation of said product in form of suspension in zone of further oxidation with formation of product of further oxidation; where said oxidation is carried out at temperature within the range from 190°C to 280°C; and where said oxidation takes place in said zone of further oxidation at temperature higher than in said primary oxidation zone; (d) crystallisation of said product of further oxidation in crystallisation zone with formation of crystallised product in form of suspension; (e) cooling of said crystallised product in form of suspension in cooling zone with formation of cooled suspension of purified carboxylic acid; and (i) filtration and optionally drying of said cooled suspension of purified carboxylic acid in filtration and drying zone in order to remove part of solvent from said cooled suspension of carboxylic acid with obtaining of said product - purified carboxylic acid.

EFFECT: purified carboxylic acid with nice colour and low level of admixtures, without using stages of purification like hydration.

8 cl, 1 tbl, 1 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method, by which the carboxylic acid/diol mixture, that is suitable as the initial substance for the manufacture of polyester, obtained from the decolourised solution of carboxylic acid without actually isolating the solid dry carboxylic acid. More specifically, the invention relates to the method of manufacturing a mixture of carboxylic acid/diol, where the said method includes the addition of diol to the decolourised solution of carboxylic acid, which includes carboxylic acid and water, in the zone of the reactor etherification, where diol is located at a temperature sufficient for evaporating part of the water in order to become the basic suspending liquid with the formation of the specified carboxylic acid/diol mixture; where the said carboxylic acid and diol enter into a reaction in the zone of etherification with the formation of a flow of a complex hydroxyalkyl ether. The invention also relates to the following variants of the method: the method of manufacture of the carboxylic acid/diol mixture, where the said method includes the following stages: (a) mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of damp carboxylic acid; where the said carboxylic acid is selected from the group, which includes terephthalic acid, isophthatic acid, naphthalenedicarboxylic acid and their mixtures; (b) discolourisation of aforesaid solution of damp carboxylic acid in the zone for reaction obtaining the decolourised solution of carboxylic acid; (c) not necessarily, instantaneous evaporation of the said decolourised solution of carboxylic acid in the zone of instantaneous evaporation for the removal of part of the water from the decolourised solution of carboxylic acid; and (d) addition of diol to the decolourised solution of carboxylic acid in the zone of the reactor of the etherification, where the said diol is located at a temperature, sufficient for the evaporation of part of the water in order to become the basic suspending liquid with the formation of the carboxylic acid/diol mixture; where the aforesaid carboxylic acid and diol then enter the zone of etherification with the formation of the flow of complex hydroxyalkyl ether; and relates to the method of manufacture of carboxylic acid/diol, where the said method includes the following stages: (a) the mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of carboxylic acid; (b) discolourisation of the said solution of damp carboxylic acid in the reactor core with the formation of the decolourised solution of carboxylic acid; (c) crystallisation of the said decolourised solution of carboxylic acid in the zone of crystallisation with the formation of an aqueous suspension; and (d) removal of part of the contaminated water in the aforesaid aqueous solution and addition of diol into the zone of the removal of liquid with the obtaining of the said carboxylic acid/diol mixture, where diol is located at a temperature sufficient for evaporating part of the contaminated water from the said aqueous suspension in order to become the basic suspending liquid.

EFFECT: obtaining mixture of carboxylic acid/diol.

29 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method, by which the carboxylic acid/diol mixture, that is suitable as the initial substance for the manufacture of polyester, obtained from the decolourised solution of carboxylic acid without actually isolating the solid dry carboxylic acid. More specifically, the invention relates to the method of manufacturing a mixture of carboxylic acid/diol, where the said method includes the addition of diol to the decolourised solution of carboxylic acid, which includes carboxylic acid and water, in the zone of the reactor etherification, where diol is located at a temperature sufficient for evaporating part of the water in order to become the basic suspending liquid with the formation of the specified carboxylic acid/diol mixture; where the said carboxylic acid and diol enter into a reaction in the zone of etherification with the formation of a flow of a complex hydroxyalkyl ether. The invention also relates to the following variants of the method: the method of manufacture of the carboxylic acid/diol mixture, where the said method includes the following stages: (a) mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of damp carboxylic acid; where the said carboxylic acid is selected from the group, which includes terephthalic acid, isophthatic acid, naphthalenedicarboxylic acid and their mixtures; (b) discolourisation of aforesaid solution of damp carboxylic acid in the zone for reaction obtaining the decolourised solution of carboxylic acid; (c) not necessarily, instantaneous evaporation of the said decolourised solution of carboxylic acid in the zone of instantaneous evaporation for the removal of part of the water from the decolourised solution of carboxylic acid; and (d) addition of diol to the decolourised solution of carboxylic acid in the zone of the reactor of the etherification, where the said diol is located at a temperature, sufficient for the evaporation of part of the water in order to become the basic suspending liquid with the formation of the carboxylic acid/diol mixture; where the aforesaid carboxylic acid and diol then enter the zone of etherification with the formation of the flow of complex hydroxyalkyl ether; and relates to the method of manufacture of carboxylic acid/diol, where the said method includes the following stages: (a) the mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of carboxylic acid; (b) discolourisation of the said solution of damp carboxylic acid in the reactor core with the formation of the decolourised solution of carboxylic acid; (c) crystallisation of the said decolourised solution of carboxylic acid in the zone of crystallisation with the formation of an aqueous suspension; and (d) removal of part of the contaminated water in the aforesaid aqueous solution and addition of diol into the zone of the removal of liquid with the obtaining of the said carboxylic acid/diol mixture, where diol is located at a temperature sufficient for evaporating part of the contaminated water from the said aqueous suspension in order to become the basic suspending liquid.

EFFECT: obtaining mixture of carboxylic acid/diol.

29 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: invention pertains to the perfection of the method of regulating quantities of dissolved iron in liquid streams during the process of obtaining aromatic carboxylic acids or in the process of cleaning technical aromatic carboxylic acids, characterised by that, to at least, part of the liquid stream for regulating the quantity of dissolved iron in it, at least one peroxide with formula R1-O-O-R2 is added. Here R1 and R2 can be the same or different. They represent hydrogen or a hydrocarbon group, in quantities sufficient for precipitation of the dissolved iron from the liquid. The invention also relates to the perfection of the method of obtaining an aromatic carboxylic acid, through the following stages: A) contacting the crude aromatic material which can be oxidised, with molecular oxygen in the presence of an oxidising catalyst, containing at least, one metal with atomic number from 21 to 82, and a solvent in the form of C2-C5 aliphatic carboxylic acid in a liquid phase reaction mixture in a reactor under conditions of oxidation with formation of a solid product. The product contains technical aromatic carboxylic acid, liquid, containing a solvent and water, and an off-gas, containing water vapour and vapour of the solvent; B) separation of the solid product, containing technical aromatic carboxylic acid from the liquid; C) distillation of at least part of the off gas in a distillation column, equipped with reflux, for separating vapour of the solvent from water vapour. A liquid then forms, containing the solvent, and in the upper distillation cut, containing water vapour; D) returning of at least, part of the liquid from stage B into the reactor; E) dissolution of at least, part of the separated solid product, containing technical aromatic carboxylic acid, in a solvent from the cleaning stage with obtaining of a liquid solution of the cleaning stage; F) contacting the solution from the cleaning stage with hydrogen in the presence of a hydrogenation catalyst and under hydrogenation conditions, sufficient for formation of a solution, containing cleaned aromatic carboxylic acid, and liquid, containing a cleaning solvent; G) separation of the cleaned aromatic carboxylic acid from the solution, containing the cleaning solvent, which is obtained from stage E, with obtaining of solid cleaned aromatic carboxylic acid and a stock solution from the cleaning stage; H) retuning of at least, part of the stock solution from the cleaning stage, to at least, one of the stages B and E; I) addition of at least, one peroxide with formula R1-O-O-R2, where R1 and R2 can be the same or different, and represent hydrogen or a hydrocarbon group, in a liquid from at least one of the other stages, or obtained as a result from at least one of these stages, to which the peroxide is added, in a quantity sufficient for precipitation of iron from the liquid.

EFFECT: controlled reduction of the formation of suspension of iron oxide during production of technical aromatic acid.

19 cl, 1 dwg, 6 ex, 4 tbl

FIELD: carbon materials and hydrogenation-dehydrogenation catalysts.

SUBSTANCE: invention relates to improved crude terephthalic acid purification process via catalyzed hydrogenating additional treatment effected on catalyst material, which contains at least one hydrogenation metal deposited on carbonaceous support, namely plane-shaped carbonaceous fibers in the form of woven, knitted, tricot, and/or felt mixture or in the form of parallel fibers or ribbons, plane-shaped material having at least two opposite edges, by means of which catalyst material is secured in reactor so ensuring stability of its shape. Catalyst can also be monolithic and contain at least one catalyst material, from which at least one is hydrogenation metal deposited on carbonaceous fibers and at least one non-catalyst material and, bound to it, supporting or backbone member. Invention also relates to monolithic catalyst serving to purify crude terephthalic acid, comprising at least one catalyst material, which contains at least one hydrogenation metal deposited on carbonaceous fibers and at least one, bound to it, supporting or backbone member, which mechanically supports catalyst material and holds it in monolithic state.

EFFECT: increased mechanical strength and abrasion resistance.

8 cl, 4 ex

FIELD: industrial production of methacrylic acids at reduced amount of industrial wastes.

SUBSTANCE: proposed method is performed by catalytic oxidation of propane, propylene or isobutylene in vapor phase at separation of final product and forming of high-boiling mixture as by-product which contains (according to Michaels addition) water, alcohol or methacrylic acid added to methacrylic group. By-product is decomposed in thermal decomposition reactor at simultaneous distillation of decomposition products in distilling column from which methacrylic acid is taken in form of distillate. Flow of liquid decomposition residue is forced for peripheral direction by means of mixing blades before withdrawal from reactor. Peripheral direction is obtained with the aid of liquid fed from the outside of decomposition reactor; to this end use is made of initial high-boiling material or flow of liquid discharged from decomposition reactor. If necessary, etherification stage is performed through interaction with alcohol for obtaining methecrylic ester. Decomposition of by-product formed at obtaining methacrylic acid by oxidation of propylene or isobutylene or at obtaining methacrylic acid by interaction of acid with alcohol by alcohol through introduction of by-product into thermal decomposition reactor provided with distilling column which has plates made in form of disks and toroids for simultaneous decomposition and distillation. Plant proposed for realization of this method includes thermal decomposition reactor and distilling column, level meters and lines for discharge of liquid containing easily polymerized compounds. Level indicator mounted at area of accumulation of liquid shows pressure differential. Line for detecting the side of high pressure of this level meter is connected with accumulated liquid discharge line.

EFFECT: updated technology; increased yield of target products.

38 cl, 14 dwg, 2 tbl, ex

FIELD: chemical technology.

SUBSTANCE: invention relates to technology for synthesis of acetic acid by the cabonylation reaction of methanol with carbon monoxide. Method involves preparing the productive flow in the reaction section containing acetic acid, acetaldehyde, water and other impurities. In the cleansing treatment the reaction products are subjected for treatment wherein acetaldehyde impurities are oxidized to either acetic acid after its isolation and recovered to the reaction zone or to carbon dioxide and water that removed from the system. As result, method provides excluding the negative effect of acetaldehyde at step for separation of the reaction products. Oxygen, air or their mixtures, ozone, carbon peroxide or peracetic acid are used as oxidant. As possible variants of the method, the productive flow is fed to distillation column wherein flow of light products or heavy products are isolated under condition that each of these flow involves acetic acid, acetaldehyde and water. Then "light" or "heavy" flow is subjected for oxidation as said above to reduce the concentration of acetaldehyde. As a variant of the method the flow of heavy products can be treated by extraction with water followed by oxidation of acetaldehyde-containing aqueous phase. Invention provides improvement of method due to exclusion of the necessity of purification of the end product from acetaldehyde impurity.

EFFECT: improved treatment method.

20 cl, 3 tbl, 35 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a thermal separation method using fractional condensation of a product-gas mixture, obtained through heterogeneous catalysed partial oxidation of propene and/or propane in gaseous phase to acrylic acid, for separating at least one mass flow, concentrated with acrylic acid, from a product-gas mixture containing acrylic acid, which involves continuous static operation of at least one device for thermal separation, containing at least one effective separation chamber with a fractionation column which has mass-transfer trays as built-in separating elements, in which the product-gas mixture is loaded, containing acrylic acid as at least one mass flow, and from which at least one mass flow containing acrylic acid is unloaded under the condition that, the overall mass flow loaded into the effective separation chamber and obtained from combining separate mass flows loaded into the separating chamber, contains X wt % components distinct from acrylic acid, the mass flow which is unloaded from the effective separation chamber with the largest content of acrylic acid, contains Y wt % components distinct from acrylic acid, ratio X:Y is ≥5, effective separation chamber, except the loading and unloading place, is bordered by a solid phase and contains, besides the mass-exchange trays as built-in separating elements in the fractionation column, at least one circulating heat exchanger, and total volume of the chamber, filled with liquid phase, is ≥1 m3, wherein temperature of the liquid phase is at least partially ≥80°C, when the effective separation chamber is divided into n separate volume elements, wherein the highest and lowest temperature of liquid phase in a separate volume element differ by not more than 2°C, and the volume element in the effective separation chamber is solid, total dwell time ttotal.

≤20 h, where A = (Ti-To)/10°C, To= 100°C, Ti = arithmetic mean value of the highest and lowest temperature of the ith volume element in the liquid phase in °C, msi = total mass of acrylic acid in the volume of the liquid phase of the ith volume element, mi = total liquid phase mass unloaded from the ith volume element, and is the sum of all volume elements i, under the condition that, volume elements i with liquid phase mass mi and as volume elements with a dead zone are also not included in the sum of all volume elements i, as well as volume elements i, which do not contain liquid phase, and total amount of liquid phase contained in volume elements with a dead zone is not more than 5 wt % of the total amount of liquid phase contained in the effective separation chamber.

EFFECT: separation of mass flow concentrated with acrylic acid.

10 cl, 12 dwg, 2 ex, 2 tbl

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