Method for synthesis of alkyl(meth)acrylates

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method for synthesis of alkyl(meth)acrylates which are used in synthesis of polymers and copolymers with other polymerisable compounds, involving a step for re-esterification of alkyl ester of α-hydroxycarboxylic acid with (meth)acrylic acid, accompanied by formation of alkyl(meth)acrylates and α-hydroxycarboxylic acid, and a step for dehydration of α-hydroxycarboxylic acid, accompanied by formation of (meth)acrylic acid.

EFFECT: method enables to obtain a product with high selectivity.

22 cl, 2 tbl, 2 dwg, 38 ex

 

The present invention relates to a method for producing alkyl(meth)-acrylates.

Esters of acrylic acid and methacrylic acid, nienasycenie alkyl(meth)-acrylates, found the main field of application in obtaining polymers and copolymers with other capable of polymerization compounds.

In addition, esters of methacrylic acid such as methyl methacrylate, is an important monomer for different special esters on the basis of methacrylic acid, which is produced by transesterification of the corresponding alcohol.

The methyl methacrylate and methacrylic acid currently mainly produced from hydrocyanic acid and acetone via formed as the main intermediate connection acetonecyanohydrin (ACG).

In the relevant patent literature described and implemented on an industrial scale other ways of getting methacrylate and methacrylic acid, involving the use of other starting compounds instead ACG. In this regard, the raw materials on the basis of hydrocarbons with four carbon atoms, such as isobutylene or tert-butanol, currently used as reagents, which in turn target derivatives of methacrylic acid by a multistage method.

An additional object of intensive ISS is adowanie was using propylene as the main raw material, and stepped hydrocarbonylation (education somaclonal acid) and oxidative dehydrogenation leads to the production of methacrylic acid with moderate output.

It is known that as the main raw material, you can use propanal or propionic acid, which can be obtained in a technically ongoing processes of ethylene and structures with one carbon atom, such as carbon monoxide. In such processes formed by the aldol condensation with formaldehyde β-hydroxycarbonyl connection dehydration in situ converted into the corresponding α,β-unsaturated compound. Overview of common methods of obtaining methacrylic acid and its esters, see, for example, in Weissermel, Agra "Industrielle organische Chemie", VCH, Weinheim 1994, 4th edition, page 305 and following, as well as in Kirk Othmer "Encyclopedia of Chemical Technology", 3rd edition, volume 15, page 357.

It is well known that the first reaction stage of technical methods based on the use of ACG (the so-called amidation ACG), have concentrated sulfuric acid (about 100% wt. H2SO4) at a temperature of from 80 to about 110°C.

Predstaviteley for such a process is, for example, patent US 4529816, in accordance with which the amidation ECG is carried out at a temperature of about 100°C. and the molar assigned and ACG to H 2SO4in the approximate range from 1:1.5 to 1:1,8. The main stages of the process according to this method are a) amidation, b) conversion and (C) etherification.

On stage amidation as the main products interactions get amide, sulfoxy-α-hydroxyisovaleric acid-hydrogen sulfate (SHEM) and amide of methacrylic acid-vodoroslevyh (POPPY×H2SO4in the form of a solution in excess of sulfuric acid. In addition, the typical solution phase amidation contains amide α-hydroxyisovaleric acid-hydrogen-sulfate (SHM×H2SO4), the output of which in terms of ACH is less than 5%. When more or less complete transformation ACG such a highly selective process amidation proceeds with a total output of these intermediates from about 96 to 97%.

However, at the stage amidation as byproducts of minor quantities of carbon monoxide, acetone, products of sulfonation of acetone and cyclocondensation products of acetone with various intermediate compounds.

Depending on the water content in the used sulfuric acid generated at the stage of amidation mixture, along with SHEM, also contains the SHM. For example, when using sulfuric acid with a concentration of 97% by weight. (1.5 equivalent of H2SO4relatively ACG) obrazu is camping for about 25% wt. The SHM that cannot selectively and completely convert to MAC. Thus, the relatively high water content at the stage performed at a temperature of from 90 to 110°C amidation causes a relatively high content of SHM, which can be converted in the usual conversion in the target intermediate product of the POPPY×H2SO4only with relatively low selectivity.

For the conversion is the most complete transformation of SHEM and SHM in POPPY flowing through β-elimination of sulfuric acid (used as a solvent excess sulfuric acid).

Thus, at the stage of conversion at elevated temperatures (140 to 160°C) and low contact time of the reactants (about 10 minutes or less) carry out the transformation contained in sulfuric acid (anhydrous) solution of the SHM, SHEM, and POPPY (in the form of corresponding hydrosulfate).

The reaction mixture of stage conversion is characterized by a significant excess of sulfuric acid and the approximate content of the main product of the POPPY×H2SO4in solution, comprising from 30 to 35% wt. (depending on the excess of sulphuric acid).

When more or less complete transformation of SHEM×H2SO4on the stage of conversion approximate output POPPY×H2SO4ranging from 94 to 95%. Thus, consistent with the om losses amidation, due to the above adverse reactions, for the subsequent esterification in the target product is a methyl methacrylate (MMA) is available only from 90 to 92% of the MAC (in terms of ATG).

By-products formed in harsh reaction conditions, the stage of conversion are a significant number of products mutual condensation and attach intermediates.

The purpose of esterification is the most complete transformation obtained at the stage of conversion POPPY × H2SO4in MMA. The esterification is performed by adding sulfuric acid to the solution POPPY mixture of water with methanol, and she, at least, partially proceeds with the formation of methacrylic acid (MAC) as an intermediate product. The etherification can be carried out under pressure or without pressure.

In the saponification/subjected to esterification conversion solution at a temperature of from 90 to 140°C. and the reaction time from one to several hours usually receive a sulfuric acid solution of MMA, POPPY and formed of hydrosulphate of ammonia.

The selectivity of the conversion of methanol at the stage of esterification due to specific reaction conditions and the presence of free sulphuric acid is only about 90% or less, and a by-product is formed from the condensation of methanol Dimitrov the th air.

When more or less complete transformation of POPPY × H2SO4approximate output of MMA at the stage of esterification is from 98 to 99% in terms of used MACS (total selectivity of the formation of the MAC+MMA). Thus, taking into account losses during amidation and conversion, due to the above adverse reactions, the maximum yield of MMA as a result of implementation including all stages of the overall process at the optimum implementation of the reaction is 90% in terms of ACG.

Along with poor overall yield of the target products, the disadvantage of the above process, the implementation of which, especially in the industrial scale, associated with the formation of significant quantities of by-products and waste gases, is to use sverdsrikhimmash quantities of sulphuric acid.

In addition, when processing containing the hydrosulphate of ammonia and sulfuric acid process acid plant for the regeneration of the contact sulfuric acid are allocated degradable solid condensation products, which prevent reliable transportation technological acid and the elimination of which is associated with significant costs.

Due to significant losses of yield of the target products that are specific to offer the frame in the patent US 4529816 way it was proposed to carry out the amidation and the hydrolysis ACH in the presence of water, while maintaining, at least in the early stages of becoming attached to molecules of hydroxyl functional groups.

Such alternatives implemented in the presence of water amidation depending on, carry them in the presence of methanol or without him, accompanied by formation or complex methyl ester 2-hydroxyisovaleric acid (GIMM), or 2-hydroxyisovaleric acid (GIMC).

2-Hydroxyadamantane acid is a key intermediate product to obtain a methacrylic acid and the corresponding esters of methacrylic acid, especially methyl methacrylate.

Another alternative is retrieved from ACG esters 2-hydroxyine-butyric acid, particularly difficult methyl ester 2-hydroxyisovaleric acid, is proposed in Japanese patent JP Hei 4-193845. In accordance with such option ACG first lidiruyut sulfuric acid is used in an amount of from 0.8 to 1.25 equivalent, in the presence of less than 0.8 equivalent of water at temperatures below 60°C, and then to transform products amidation in YMCM or the corresponding esters are subjected to interaction at temperatures above 55°C with alcohol, especially methanol, are used in quantities of more than 1.2 is equivalent. Information about the presence of a viscosity reducing environments, stable relative to the reaction matrix in the specified publication no.

Disadvantages and problems of the technical implementation of the above method due to the extremely strong increase of viscosity at the final stage of the reaction.

In the patent literature contains some compounds that are destined for recycling and conversion YMCM dehydration in methyl methacrylate.

For example, according to European patent EP 0429800 YMCM or mixture YMCM with the corresponding alpha - or beta-alkoxycarbonyl complex ester is subjected to conversion in the gas phase in the presence of methanol as a shared source component on a heterogeneous catalyst comprising a crystalline aluminosilicate and a mixed impurities consisting of alkali metal, on the one hand, and a noble metal, on the other hand. Although, at least in the beginning of the reaction, the catalyst provides a satisfactory degree of conversion and selectivity, but as the continuation of the reaction the catalyst rather rapidly loses its activity, which is accompanied by a decrease in output.

A similar structure is proposed in European patent EP 0941984 that describes the gas-phase dehydration YMCM in the form of a separate phase of the synthesis of MMA, realizable is in the presence of a heterogeneous catalyst, consisting of salts of alkali metal and phosphoric acid for the silicon dioxide. However, the corresponding multistage technology in General very complex, some stages will be sold at high pressure, and therefore, using expensive equipment, and it does not provide a satisfactory output.

Along with the above publications related to the dehydration of GIMM and related esters in the gas phase and their transformation into the corresponding alpha-beta unsaturated derivatives of methacrylic acid, dehydration proposed to be carried out in the liquid phase.

Getting MAC from 2-hydroxyisovaleric acids are described, for example, in patent US 3487101 in which the proposed liquid-phase synthesis of various derivatives of methacrylic acid, first of all, methacrylic acid and its esters, 2-hydroxyisovaleric acid, characterized in that the transformation GIMC in methacrylic acid is carried out in the presence of dissolved alkaline catalyst at a high temperature component from 180 to 320°C., in the presence of high-boiling esters (for example, dimethylphthalate) and inner anhydrides (e.g. phthalic anhydride). According to this patent, the selectivity of the formation of the MAC at degrees of conversion GIMC exceeding 90%, up to 98%. Information regarding the long-term stability of the slurry catalyst, first of all depletion anhydride used, not available.

In addition, in Japanese patent JP 184047/1985 considered dehydration YMCM in the presence of concentrated sulfuric acid (concentration of from 90 to 100% wt.). The drawback of this method is the increased consumption of sulfuric acid and the release of large quantities of aqueous sulfuric acid resulting from the allocation of water from YMCM as a result of dehydration. In connection with the formation of large quantities of spent sulphuric acid specified method is not economic values.

German patent application DE-OS 1191367 relates to the production of methacrylic acid from 2-hydroxyisovaleric acid in the liquid phase, characterized in that the transformation GIMC in methacrylic acid is carried out in the presence of polymerization inhibitors (e.g., such as copper powder) and a mixture of catalysts consisting of metal halides and alkali metal halides, at a high temperature component from 180 to 220°C. According to the specified application selectivity of the formation of the MAC at degrees of conversion GIMC greater than 90%, more than 99%. The best results are achieved by using mixtures of catalysts based on zinc bromide and lithium bromide. However, it is well known that the use of containing halide catalysts at high the temperatures imposes stringent requirements on structural materials used, the problems caused by the presence in the distillate carry out the halogenated by-products, also apply to subsequent nodes of the process equipment.

From European patent EP 0487853 known to produce methacrylic acid from acetonecyanohydrin, characterized in that the first stage ACG subjected to contact with water at moderate temperatures in the presence of a heterogeneous catalyst for hydrolysis, in the second stage interact amide 2-hydroxyisovaleric acid with methylformate or methanol/carbon monoxide, leading to the formation of formamide and complex methyl ester hydroxyisovaleric acid, in the third stage, YMCM in the presence of heterogeneous ion exchanger omelet water to hydroxyisovaleric acid, and in the fourth stage are dehydration GIMC in the liquid phase at high temperatures in the presence of dissolved salts of alkaline metal. Methacrylic acid is obtained from GIMC with high degrees of conversion (99%) and more or less quantitative selectivity. However, due to the need for a large number of reaction stages and intermediate assignment of individual intermediates, and in particular in connection with the necessity of implementation of the process at elevated pressure, the Institute of technology is too complex, and therefore, ultimately unprofitable. In addition, it is necessary to synthesize formamid, which is often seen as an unintended by-product to be disposed of.

In the German patent application DE-OS 1768253 describes a method for methacrylic acid by dehydration of α-hydroxyisovaleric acid, characterized in that GIMC subjected to liquid-phase transformation at a temperature of at least 160°C., in the presence of a dehydration catalyst, which is a metal salt of α-hydroxyisovaleric acid. Particularly suitable in this case are the salt GIMC with alkaline and alkaline earth metals, which can be obtained in the melt GIMC in situ in the transformation of suitable metal salt. According to this publication output from POPPY GIMC reaches 95%, and the initial reaction mixture during continuous operation of the process contains GIMC and about 1.5% wt. salt GIMC with the alkaline metal.

From the patent RU 89631 a method of obtaining methacrylic acid from 2-hydroxyisovaleric acid by elimination of water in the liquid phase, characterized in that the reaction is carried out in the absence of catalyst in aqueous solution GIMC (up to 62% wt. GIMC in water) under pressure and at elevated temperatures comprising from 200 to 240°C.

In addition, and what is known about how to obtain 2-hydroxyisovaleric acid from acetonecyanohydrin, which can be implemented by saponification nitrile functional groups in the presence of mineral acids (see J. Brit. Chem. Soc. (1930) and Spetses (1939), 800).

In accordance with the process of this type is known, for example, from Japanese patent JP Sho 63-61932, 2-hydroxyisobutyryl acid (GIMC) receive a two-step saponification ACG. In this first ATG in the presence of from 0.2 to 1.0 mole of water and from 0.5 to 2 equivalents of sulfuric acid is transformed into the corresponding amide salt. Already at this stage, involving the use of small amounts of water and sulfuric acid necessary to ensure high yields, and reduce the time of reaction and formation of small quantities of waste technological acid, faced with a serious problem of suitability amigurami mixture for mixing, due to its high viscosity, especially at the final stage of the reaction.

Increasing the amount of water to reduce viscosity leads to a sharp slowdown amidation and side reactions, especially the slicing ACG on educti (acetone and hydrocyanic acid), which under reaction conditions to form products consistently occurring reactions. Although the temperature rise in accordance with the Japanese patent JP SHO 63-61932 and allows you to adjust the viscosity of the reaction mixture, the lower of which provides the t able stirring the reaction compositions, however, in this case, already at moderate temperatures also dramatically increases the flow of adverse reactions, which ultimately manifests itself in a reduced yield of the target product (see comparative examples).

When carrying out the amidation at low temperatures (below 50°C), i.e. in conditions that could provide a higher selectivity to the end of the reaction due to the increase in the concentration of the hardly soluble in the reaction conditions amide salts first is the formation of hard stirred suspension, and then complete the hardening reaction system.

In the second stage proposed in Japanese patent JP SHO 63-61932 method to the resulting amidation solution add water and carry out the hydrolysis at the same amidation elevated temperature, and obtained by amidation of salts formed 2-hydroxyadamantane acid (GIMC) with the simultaneous release of free hydrosulphate of ammonia.

To ensure the profitability of technical process, along with selective education GIMC as the target reaction product, great importance is its isolation from the reaction matrix, respectively, Department GIMC from residual process acid.

In accordance with the Japanese patent JP Sho 57-131736 m the mode of α-oxidizable acid (GIMC) this problem is solved due to processing containing α-hydroxyisobutyryl acid and sour hydrosulphate of ammonium reaction solution, the resulting hydrolytic cleavage of acetonecyanohydrin by its interaction with sulfuric acid and water, extracting agent, and 2-hydroxyadamantane acid goes into extracting agent and acidic ammonium sulfate remains in the aqueous phase.

In accordance with a specified technology with the aim of increasing the degree of extraction GIMC organic extractant contained in the reaction system of free sulfuric acid before extraction thanks to neutralize the alkaline processing environment. Neutralization of sulfuric acid is associated with significant additional costs amine or mineral substrate and the formation of significant amounts of waste in the form of corresponding salts, which cannot be disposed of without adverse impacts on the ecology and economy of the process.

Thus, the disadvantages of the proposed in Japanese patent JP Sho 57-131736 way for MMA via amide of methacrylic acid - hydrosulfate (reaction sequence: amidation - conversion - hydrolytic etherification) are as follows.

a) Use a significant molar excess of sulphuric acid relative to ATG (technically involved in the process from about 1.5 to 2 equivalents of sulfuric acid to 1 equivalent ACG).

b) Significant loss of output on stadiumvalue (approximately 3 to 4%) and stage conversion (about 5 to 6%), which ultimately negatively affects the maximum output amidosulfuron methacrylic acid of about 91%.

c) Significant waste streams in the form of aqueous sulfuric acid with dissolved hydrosulphate of ammonium and organic byproducts. Selection degradable residues of uncertain composition of such waste technological acid requires additional processing, respectively costly disposal.

Disadvantages proposed in Japanese patent JP Sho 57-131736 way for MMA through hydroxyisobutyryl acid as the primary intermediate compounds (reaction sequence: amidation - hydrolytic synthesis GIMC - synthesis POPPY - hydrolytic etherification) can be summarized as follows.

a) the Use of sulfuric acid, even when a slight molar excess relative to ATG (not more than 1.0 equivalent of sulfuric acid to one equivalent ECG) leads to serious problems caused by the increased viscosity and lack of suitability amigurami environment for stirring, until complete solidification of the reaction of compounds; the proposed thinning alcohols (methanol) or various esters used for the amidation reaction conditions leads to an incomplete is represeni ACG, a sharp increase in the occurrence of adverse reactions or chemical decomposition of diluents.

b) Significant loss of output stage amidation (about 5 to 6%) and expensive extraction with an organic solvent, followed by formation containing water and GIMC phase extracting agent, the selection GIMC from which the distillation is associated with increased energy consumption. For every kilogram GIMC approximately two kilograms of waste generated technological acid containing about 34 wt.%. water and 66% wt. of hydrosulphate of ammonia (see example 4 in Japanese patent JP Sho 57-131736). Regeneration of the spent salt solution with a high water content at the facility for contact sulfuric acid requires a considerable amount of energy, which significantly limits the production capacity of such installations.

A common feature of all the above methods is extremely expensive selection GIMC of containing the hydrosulphate of ammonia water of the reaction matrix. The presence of too much water in the containing GIMC extraction phase also determines the ablation of hydrosulphate of ammonia for the next stage of the synthesis POPPY, continuous implementation in technical scale within reasonable period of time does not seem POS of the Noi. In addition, the proposed methods due to the high energy costs of regeneration as water-containing highly concentrated technological acid, and extraction streams are unprofitable and cannot serve as a true alternative though selective, but reliable technology, leading to the ultimate goal through the implementation of a small number of simple technological operations.

Taking into account the above prior art, the present invention was based on the task to provide a method for production of alkyl(meth)acrylate, which is simple and economical implementation.

Another objective of the present invention was to develop ways to get the alkyl(meth)acrylates with extremely high selectivity.

In addition, the present invention was based on the task to provide a method for production of alkyl(meth)acrylates, which would be accompanied by the formation of only minor amounts of by-products. The target product, you must obtain the highest possible outputs when low aggregate consumption.

Another objective of the present invention was to propose a method for production of alkyl(meth)acrylates, which can be carried out particularly simply and economy is ichno.

The above objectives and other objectives of the invention are not explicitly formulated, but surely arising out of context descriptions, solved by the way, the hallmarks of which is set out in paragraph 1 of the claims. Viable options proposed in the invention method are provided in the respective dependent claims.

Thus, an object of the present invention is a method for production of alkyl(meth)acrylates, including the state interesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid, followed by the formation of alkyl(meth)acrylate and α-hydroxycarbonic acid, and the stage of dehydration of α-hydroxycarbonic acid, followed by education (meth)acrylic acid.

Thanks to the implementation proposed in the invention of operations can be achieved, in particular, the following advantages.

The method eliminates the use of large quantities of sulfuric acid as a reagent. Therefore, in accordance with the proposed invention in no way produce large amounts of waste hydrosulphate of ammonia.

The alkyl(meth)acrylates obtained proposed in the invention method, are formed with high yields. First of all, this is ranovitsa obvious from the comparison proposed in the invention method with the method, described in European patent application EP-A-0941984, according to which complex alkalemia esters of α-hydroxycarbonic acid is subjected to the direct dehydration in the alkyl(meth)acrylates. Unexpectedly, it was found that, due to the additional reaction stage interesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid, and ultimately achieve higher selectivity values.

This formed a very minor amounts of by-products. In addition, first and foremost, given the high selectivity achieve high degrees of conversion.

Proposed in the invention method leads to the formation of minor amounts of by-products.

Proposed in the invention, the method can be implemented cost-effective and, above all, with little energy consumption. Used for dehydration and interesterification catalysts can be operated for an extended period of time without reducing the selectivity or activity.

Proposed in the invention, the method can be implemented on an industrial scale.

According to the invention complex alkilany ether α-hydroxycarbonic acid is subjected to interaction with (meth)acrylic acid. The (meth)acrylic acid are known, and Vlada commercially available products. Along with acrylic acid (propanolol acid) and methacrylic acid (2-methylpropenoic acid) such acids, first and foremost, the corresponding substituted derivatives. Suitable substituents are, primarily, are halogen, such as chlorine, fluorine and bromine, and alkyl groups which preferably can contain from 1 to 10, particularly preferably from 1 to 4 carbon atoms. Suitable acids are, in particular, β-methylacrylate acid (butenova acid), α,β-dimethylacrylic acid, β-ethylacrylate acid, β,β-dimethylacrylic acid. The preferred acids are acrylic acid (Papanova acid) and methacrylic acid (2-methylpropenoate acid), and particularly preferred is methacrylic acid.

Subjected to interesterification complex alkalemia esters of α-hydroxycarbonic acid esters are known, an alcoholic residue which preferably contains from 1 to 20, especially from 1 to 10, particularly preferably from 1 to 5 carbon atoms. The preferred alcohol remains primarily occur from methanol, ethanol, propanol, butanol, in particular n-butanol and 2-methyl-1-propanol, pentanol, hexanol and 2-ethylhexanol, and especially preferred alcohol residues derived from the methanol and etano the A.

Acid residue is subjected to interesterification complex alilovic esters of α-hydroxycarbonic acid is preferably derived from (meth)acrylic acid, which can be obtained by dehydration of α-hydroxycarbonic acid. For example, if the use of methacrylic acid, then subjected to interesterification ester α-hydroxyisovaleric acid. In the case of using acrylic acid interesterification preferably subjected to an ester of α-hydroxyisopropyl acid.

Preferably used complex alkylamino esters of α-hydroxycarbonic acid are the methyl ester of α-hydroxypropionic acid complex ethyl ester of α-hydroxypropionic acid, methyl ester of α-hydroxyisovaleric acid and complex ethyl ester of α-hydroxyisovaleric acid.

Such complex alkalemia esters of α-hydroxycarbonic acid often with optimal costs obtained from the relevant cyanhydrins. The degree of purity of cyanhydrin is not critical. Therefore, for the implementation of hydrolysis can use peeled or unpeeled cyanhydrin. In accordance with these be used according to the invention complex alkalemia esters of α-hydroxycarbonic acid can be synthesized from ketones and is of Legalov, and hydrocyanic acid and the corresponding alcohol.

The first stage is similar to the synthesis of carbonyl compound, for example, ketone, first of all, acetone, or aldehyde, for example acetaldehyde, propanal or butanol, turn in the appropriate cyanhydrin interaction with hydrocyanic acid. When this transformation, typically carried out using as catalyst a minor amount of alkali or amine, particularly preferably subjected to acetone and/or acetaldehyde.

Received cyanhydrin next stage is subjected to contact with water, followed by amide formation hydroxycarbonate acid.

This interaction typically carried out in the presence of a catalyst. For this purpose, first of all, suitable catalysts based on manganese oxide described, for example, in European patent applications EP-A-0945429, EP-A-0561614 and EP-A-0545697. This manganese oxide can be used in the form of manganese dioxide obtained carried out in the acidic environment of the processing of manganese sulfate potassium permanganate (see Biochem.J., 50, page 43 (1951) and J.Chem.Soc., 1953, page 2189, 1953) or electrolytic oxidation of manganese sulfate in aqueous solution. In General, the catalyst is often used in the form of a powder or granulate particles of a suitable size. The AOC is e, the catalyst may be supported on a carrier. In this case, first of all, you can also use reactors with suspended or fixed bed of catalyst, in particular, is described in European patent application EP-A-956 898.

In addition, the hydrolysis reaction of cyanhydrin can be catalysed by enzymes. Suitable enzymes are, in particular, nitrilimines. Such a reaction is described, for example, in "Screening, Characterization and Application of Cyanide-resistant suffix Hydratases" Eng. Life. Sci. 2004, 4, No. 6.

Along with this, the hydrolysis reaction of cyanhydrin can be catalysed by acids, in particular sulfuric acid. Acid catalysis is proposed to use, in particular, in Japanese patent JP Hei 4-193845.

The water required for the implementation of hydrolysis of cyanhydrin, can often be used as a solvent. The molar ratio of water to cyanhydrin is preferably at least 1:1 and particularly preferably is in the range from 0.5:1 to 25:1, even more preferably in the range from 1:1 to 10:1.

Used for hydrolysis of water may have a high degree of purity. However, this condition is not mandatory. So, for example, along with fresh water, you can also use production or process water, containing more or less significant amounts of impurities. Therefore, hydrolysis is possible and the user is also circulating water.

In addition, used for hydrolysis of cyanhydrin the reaction mixture can contain other components. Such components include, in particular, aldehydes and ketones, primarily those that were used for the synthesis of cyanhydrin. For example, the reaction mixture may contain acetone and/or acetaldehyde. Such a reaction mixture is provided, for example, in patent US 4018829-A. the Degree of purity of the added aldehydes and/or ketones in the General case is not particularly critical. Therefore, these materials may contain impurities, primarily alcohols, e.g. methanol, water and/or methyl ester of α-hydroxyisovaleric acid (GIMM). The amount used in the reaction mixture of carbonyl compounds, especially, acetone and/or acetaldehyde, can be varied within wide limits. The preferred amount of the carbonyl compound is from 0.1 to 6 moles, preferably from 0.1 to 2 moles per mole of cyanhydrin.

The temperature at which the hydrolysis reaction, in the General case can be in the range from 10 to 150°C., preferably from 20 to 100°C. and particularly preferably from 30 to 80°C.

Hydrolysis of cyanhydrin can be done, for example, in a reactor with a stationary or suspended catalyst bed.

P is obtained in this way the reaction mixture, along with the target amidon hydroxyacids, in the General case contains other components, primarily neprevyshenie cyanhydrin, and, if necessary, used acetone and/or acetaldehyde. In accordance with this, the reaction mixture can be subjected to cleaning, in which neprevyshenie cyanhydrin can be split to acetone and hydrocyanic acid, which again is used for cyanhydrin. The same applies to selected the acetone and/or acetaldehyde.

In addition, the purified reaction mixture containing the amide hydroxy acids can be released from other components by passing through a column with ion exchange resins.

As ion exchange resins, first of all, you can use the cation exchangers and anion exchangers. Suitable ion exchangers are known products. For example, suitable cation exchangers can be obtained by sulfonation of the copolymer of styrene with divinylbenzene. Alkaline anion exchange resin containing Quaternary ammonium groups covalently connected to the copolymers of styrene with divinylbenzene.

The stage of obtaining the amides of α-hydroxycarbonic acid are discussed in detail, in particular, in European patent application EP-A-0686623.

Received the above image amide α-hydroxycarbonic acid at the next stage may be preverse the complex alkilany ether α-hydroxycarbonic acid. An appropriate response can be implemented, for example, when using alkylphosphates. Suitable, above all, is mailformat or a mixture of methanol with carbon monoxide (an example of such reactions is given in European patent application EP-A-0407811).

Amide α-hydroxycarbonic acid preferably is subjected to alcoholysis with an alcohol preferably 1-10, particularly preferably 1-5 carbon atoms. The preferred alcohols are, in particular, methanol, ethanol, propanol, butanol, first of all, n-butanol and 2-methyl-1-propanol, pentanol, hexanol, heptanol, 2-ethylhexanol, octanol, nonanol and decanol. Particularly preferred alcohol is methanol and/or ethanol, more preferred alcohol is methanol. The interaction of amides of carboxylic acids with alcohols to obtain esters of carboxylic acids is well known reaction. The above reaction can be accelerated by using, for example, alkaline catalysts. The catalysts can be homogeneous or heterogeneous.

To homogeneous catalysts include alkali metal alcoholate and ORGANOMETALLIC compounds containing titanium, tin or aluminum. As the catalyst is preferably used alcoholate of titanium or tin alcoholate, for example, tetraisopropoxide titanium or tetrabutyl the ID of the tin. For the heterogeneous catalysts are, in particular, magnesium oxide, calcium oxide, and the above alkali ion.

The molar ratio of amide α-hydroxycarbonic acid to alcohol, for example, amide α-hydroxyisovaleric acid to methanol, is not critical and preferably ranges from 2:1 to 1:20.

The reaction temperature can be varied within wide limits, and the reaction rate with increasing temperature in General is increasing. The upper limit of the temperature range in the General case corresponds to the boiling temperature of the used alcohol. The reaction temperature is preferably from 40 to 300°C., particularly preferably from 160 to 240°C. depending on the temperature of the reaction can be performed under vacuum or overpressure. Consider the reaction is carried out at a pressure preferably in the range from 0.5 to 35 bar, particularly preferably from 5 to 30 bar.

The formed ammonia is typically removed from the reaction system and the reaction is often carried out at the boiling point.

Released during the alcoholysis ammonia can simple method of recycling in the entire process. So, for example, ammonia can be subjected to interaction with methanol, resulting in the formation of hydrocyanic sour the s. This interaction is proposed, for example, in European patent application EP-A-0941984. In addition, ammonia and methane can be used for the synthesis of hydrocyanic acid by the method of organization of the SCA or method Androsova shown in Ullmann''s Encyclopedia of Industrial Chemistry, 5th edition (CD-ROM), partition Inorganic Cyano Compounds".

At the next stage complex alkilany ether α-hydroxycarbonic acid is subjected to interaction with (meth)acrylic acid, leading to the formation of alkyl(meth)acrylate, and α-hydroxycarbonic acid.

Along with these reagents, the reaction mixture may contain other components, such as solvents, catalysts, polymerization inhibitors and water. The interaction of ester alkylhydroxylamines acid with (meth)acrylic acid can catalyze at least one acid or at least one base. While you can use it as homogeneous and heterogeneous catalysts. Particularly suitable acidic catalysts are primarily inorganic acid, for example sulphuric acid or hydrochloric acid, and organic acids, for example, sulfonic acids, primarily p-toluensulfonate, as well as acidic cation exchange resin.

Particularly suitable cation exchange resins, especially, are copolymers of styrene and di is invention, containing sulfonylurea group. Particularly suitable cation exchange resin manufactured by Rohm&Haas under the trade name Amberlyst®and the company Voeg under the trade name Lewatit®.

The concentration of catalyst is preferably from 1 to 30 wt.%, particularly preferably from 5 to 15% wt. in terms of the amount of initial reagents: complex ester of α-alkylhydroxylamines acid and (meth)acrylic acid.

It is preferably used for the polymerization inhibitors include, in particular, phenothiazines, tert-butylcatechol, onomatology ether of hydroquinone, hydroquinone, 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy or mixtures thereof, and the effectiveness of these inhibitors to some extent can be improved through the use of oxygen. The polymerization inhibitors can be used in concentrations of from 0.001 to 2.0 wt.%, particularly preferably from 0.01 to 0.2 wt.%. in terms of the amount of initial reagents: complex ester of α-alkylhydroxylamines acid and (meth)acrylic acid.

The transesterification is preferably carried out in the temperature interval from 50 to 200°C., particularly preferably from 70 to 130°C., especially from 80 to 120°C. even more preferably from 90 to 110°C.

Depending on the temperature of the transesterification can be performed under vacuum or overpressure. Peredery is icatio preferably carried out under pressure, components from 0.02 to 5 bar, especially from 0.2 to 3 bar and particularly preferably from 0.3 to 0.5 bar.

The molar ratio of (meth)acrylic acid to complex alkylamino ether, α-hydroxycarbonic acid is preferably in the range from 4:1 to 1:4, especially from 3:1 to 1:3 and particularly preferably from 2:1 to 1:2.

Selectivity is preferably at least 90%, particularly preferably 98%. Selectivity is defined as the ratio of the total amount of the formed alkyl(meth)acrylate and α-hydroxycarbonic acids to the total quantity of the transformed initial reagents: complex Olkiluoto ester α-hydroxycarbonic acid and (meth)acrylic acid.

According to a special variant of implementation of the present invention the transesterification can be carried out in the presence of water. The water content is preferably from 0.1 to 50 wt.%, particularly preferably from 0.5 to 20% wt. and even more preferably from 1 to 10% wt. in terms of weight used complex Olkiluoto ester α-hydroxycarbonic acid.

It has been unexpectedly discovered that the addition of minor amounts of water can improve the selectivity of interesterification. Despite the addition of water quantity resulting methanol suddenly able to maintain at a low level. When the concentration of the emission of water, component 10 to 15% wt. in terms of weight used complex Olkiluoto ester α-hydroxycarbonic acid, the reaction temperature of 120°C and its duration, respectively, the residence time of the reactants comprising from 5 to 180 minutes, preferably formed less than 5% wt. of methanol.

The transesterification can be performed in batch or continuous mode, and preferred is a continuous transesterification.

Duration interesterification depends on the molecular weight of the parent compounds, but also on the reaction temperature, and these parameters can be varied in a wide range. The reaction time of the transesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid is preferably from 30 seconds to 15 hours, particularly preferably from 5 minutes to 5 hours and even more preferably from 15 minutes to 3 hours.

When carrying out the transesterification in the continuous mode, the residence time of the reactants is preferably from 30 seconds to 15 hours, particularly preferably from 5 minutes to 5 hours and even more preferably from 15 minutes to 3 hours.

Upon receipt of methyl methacrylate from the complicated methyl ester of α-hydroxyisovaleric acid, the temperature is preferably from 60 to 130°C., particularly preferably from 80 to 120°and even more preferably from 90 to 110°C. The pressure is preferably in the range from 50 to 1000 mbar, particularly preferably in the range from 300 to 800 mbar. The molar ratio of methacrylic acid to complex methyl ether, α-hydroxyisovaleric acid preferably corresponds to the interval from 2:1 to 1:2, first of all, from 1.5:1 to 1:1,5.

The transesterification can be performed, for example, in the installation shown in figure 1. Ester hydroxycarbonic acid, for example, methyl ester hydroxyisovaleric acid, pipeline (1) into the reactor (3) with a fixed bed cation exchange resin. (Meth)acrylic acid, for example, 2-methylpropanoyl acid, is introduced into the reactor (3) from the stationary layer by pipeline (2) or pipe (17). To reduce the number of power supply lines of the reactor pipe (2) can be connected to other pipelines, for example, with the conduit (9) and pipe (13). However, the pipeline (9), (13) and/or (17) can also be directly connected to the reactor (3) with the stationary layer. In the above reaction conditions formed the reaction mixture, which, along with methanol, and neprevzaidennymi difficult methyl ether hydroxyisovaleric acid and methacrylic acid contains the reaction products: hydroxyisobutyryl acid and methyl methacrylate. Specified, the reaction mixture TP is aprovado (4) is sent to a distillation column (5). In the distillation column (5) as the head of product are water, methyl methacrylate and methanol, which are in the pipeline (7) is sent to the phase separator (8). The upper phase consisting of methyl methacrylate and methanol, is removed from the system through the pipeline (10). The lower phase separator phase (8) primarily contains water, which can be removed from the system through a pipeline (11), or sent through a pipeline (9) into the reactor (3) with the stationary layer.

In Cuba distillation column (5) can be methyl ester hydroxyisovaleric acid, hydroxyadamantane acid and methacrylic acid, which are in the pipeline (6) can be allocated to the second distillation column (12). In column (12) are complex distillation methyl ester hydroxyisovaleric acid and methacrylic acid, which by pipeline (13) return to the transesterification. Contained in the cube distillation column (12) hydroxyisobutyryl acid pipeline (14) is sent to the reactor (15) for dehydration. The resulting dehydration of methacrylic acid by pipeline (17) can be used for transesterification or withdrawn from the system through the pipeline (16).

In accordance with a particularly preferred embodiment of the invention the transesterification can the implement in the distillation column. Thus the catalyst may be in any area of the distillation column. For example, it may be in Cuba or in the column. However, it should be possible to bring doctow in contact with the catalyst. In addition, the catalyst may be in a separate zone of the distillation column, which is connected with its other areas, for example, cube and/or the column. Such a separate location area of the catalyst is preferred.

Due to the above preferred option is unexpectedly possible to increase the selectivity of interesterification. In this regard, it should be noted that the pressure of the interesterification reaction can be adjusted independently from the internal pressure in the distillation column. This allows you to maintain a low boiling temperature without increasing the reaction time, respectively, the residence time of the reactants. In addition, the reaction temperature can be varied within wide limits. Due to this it is possible to reduce its duration. Along with this is the possibility of arbitrary choice of the volume of the catalyst, regardless of the geometrical parameters of the distillation column. It is also possible, for example, to add additional reagent. All of the above technical measures increase selek is Yunosti and performance when encountered unexpectedly achieve synergistic effects.

Under this option difficult alkilany ether α-hydroxycarbonic acid, for example, methyl ester of α-hydroxyisovaleric acid is introduced into the distillation column. In addition, in the column enter the (meth)acrylic acid, for example methacrylic acid. The distillation is preferably carried out under such conditions that the Stripping was to be strictly one product, while another product remained in Cuba and were subjected to continuous removal of the cube. When using alcohols with a small number of carbon atoms, especially ethanol or methanol from the reaction mixture preferably distilled alkyl(meth)acrylate. Educti periodically passed through the area of the catalyst. Consequently, the continuously formed alkyl(meth)acrylate, and α-hydroxycarbonyl acid.

The preferred implementation of the reactive distillation is shown schematically in figure 2. Educti can be fed to a distillation column (3) overall pipeline (1) or two separate lines (1) and (2). Supply doctow preferably carried out by separate pipelines. Thus educti you can enter the same degree of separation or at any point of the column.

In this case, the temperature of the reactants at the inlet of the column can be adjusted by means of the heat required for this is equipment not shown in figure 2). In a preferred embodiment, educti served in the column separately, and boiling component is injected below the point of feed of the high-boiling component. In this case, boiling component is preferably introduced in a gaseous state.

For the implementation of the present invention can be used with any multi-stage distillation column (3) with two or more degrees of separation. The number of stages of separation according to the present invention indicate the number of plates of plate columns or the number of theoretical stages of separation Packed columns or columns with the elements of the nozzle.

Examples of the Poppet a multi-stage distillation columns can serve columns with cap, mesh, tunnel, valve, slit, setcachedevice, setdatabasename, dubovyi or centrifugal plates, examples of multistage distillation columns with elements of nozzles are pillars with rings process, Lessing rings, rings PAL, seated the Burleigh or Intalox saddles, examples of the Packed multi-stage distillation columns are columns with a nozzle type Mellapak (Sulzer), Rombopak (firm Kühni), Montz-Pak (firm Montz) and cap with the slots of the catalyst, for example, Kata-Pak.

In addition, you can also use a combination of distillation column, include the th zone plates, zone with elements of nozzles or areas with attachments.

Column (3) can be equipped with additional nodes. The column preferably includes a capacitor (12) for condensing vapor and the VAT evaporator (18).

Distillation system preferably has at least one zone, below called the reactor, which is filled with at least one catalyst. Such a reactor can be inside the distillation column. However, such a reactor preferably is located in a separate area outside of the column (3), and one of these preferred variants of the embodiment are shown in detail in figure 2.

For the implementation of the interesterification in a separate reactor (8) part flowing down inside the column of the liquid phase can be captured through the drive and output from the column in a separate thread (4). The position of the drive is determined by the concentration profile of the individual components in the column. At this concentration profile can be adjusted by varying the temperature and/or phlegmy. The drive is preferably fitted so that the output from the column flow contained both reagents, particularly preferably in a sufficiently high concentration and even more preferably at a molar ratio of acid to ether complex, located in the range from 1.5: 1:1,5. In addition, there may be several in different locations distillation columns of drives, and the molar ratio can be adjusted by the number of selected reagents.

In addition, to regulate the ratio of acid to complex the ether in the cross-products of interesterification or increase its selectivity to the output from the column flow you can add additional reagent, such as water. Add water, you can enter from the outside through the respective pipeline (figure 1 it is not shown) or select it from the phase separator (13). The pressure of the enriched water flow (5) can then be further enhanced by the device (6) to increase the pressure, for example, a pump.

The increased pressure of the stream (5) reduces, respectively, to prevent the formation of steam in the reactor, for example, in a reactor with a fixed bed of catalyst. This makes it possible to provide a uniform transmission of the flow through the reactor and the wetting of the catalyst particles. The thread can be passed through the heat exchanger (7) to regulate the desired temperature interesterification. However, depending on the needs of the stream may be subjected to heating or cooling. In addition, the variation of temperature interesterification allows you to adjust the ratio of ester to acid is in the reaction products.

In the reactor (8) is fixed catalyst bed of the interesterification reaction. The reaction mixture can pass through the reactor from top to bottom or from bottom to top. Coming out of the reactor a stream (9) with a certain amount of reaction products and neprivrednih of doctow dependent on the residence time of the reactants in the reactor, the mass of the catalyst, the reaction temperature and the ratio of doctow, and the number of added water, is first passed through a heat exchanger (10)to adjust the flow temperature, is preferred for its subsequent introduction into the distillation column. The flow temperature is preferably adjusted so that it corresponds to the temperature of the distillation column at the point of introduction of the stream.

When the insertion point in the column is recycled from the reactor flow may be located above or below the sampling point flow, directed from the column in the reactor, however, the insertion point specified stream preferably is located above the sampling point. Recirculatory in the column flow can be subjected to throttling by valve (11), and the pressure of the throttled flow adjust so that it is preferably similar to the pressure in the column. In a preferred embodiment, the pressure in the distillation column below the pressure of dresselian the th thread. The advantage of this option is that it lowers the boiling point to be separate components, allowing the distillation can be performed at lower temperatures, i.e. in conditions more favorable from the point of view of power consumption and thermal exposure of the reagents.

In the distillation column (3) carry out the separation of a mixture of reaction products. Low-boiling components, which are preferably formed by interesterification esters are distilled off via the top of column. The distillation column is preferably operated in a mode that allows you to repel added before the reactor with a stationary layer of water in the downstream product. Emerging from the upper part of the column vapor stream is condensed in the condenser (12), and the resulting condensate is subjected to separation in a settling tank (13) to the aqueous phase and a phase containing the target ester. The aqueous phase can be sent through a pipeline (15) for processing or pipeline (17) is completely or partially recycled to the transesterification. Part of the stream containing the ether phase can be returned to the column through a pipeline (14) as phlegmy (16) or withdrawn from the distillation column. High-boiling components (preferably the resulting cross-interesterification is islote) output from the column (19) in the form of the cubic stream.

Using the above preferred option unexpectedly allows you to increase the selectivity of interesterification. In this connection it should be noted that the pressure of the interesterification reaction can be adjusted independently from the internal pressure in the distillation column. This allows you to maintain a low boiling temperature without increasing the duration of the reaction, respectively, the residence time of the reactants. In addition, the temperature interesterification can be varied within wide limits. Due to this it is possible to reduce its duration. Along with this is the possibility of arbitrary choice of the volume of the catalyst, regardless of the geometrical parameters of the distillation column. It is also possible, for example, to add additional reagent.

The resulting transesterification of α-hydroxycarbonyl acid, for example, hydroxyisobutyryl acid, can be degidratiruth known methods. In the General case of α-hydroxycarbonyl acid, for example, α-hydroxyisobutyryl acid, is heated in the presence of at least one metal salt, for example, salts of alkaline and/or alkaline earth metal, at a temperature of from 160 to 300°C., particularly preferably from 200 to 240°C, and in General get a (meth)acrylic acid, and water. Suitable salts is of atalla are in particular, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, magnesium hydroxide, sodium sulfite, sodium carbonate, potassium carbonate, strontium carbonate, magnesium carbonate, sodium bicarbonate, sodium acetate, potassium acetate and sodium dihydrophosphate.

Dehydration of α-hydroxycarbonic acid can preferably be carried out under a pressure of from 0.05 to 2.5 bar, particularly preferably from 0.1 to 1 bar.

According to a special variant of implementation of the present invention dehydration carried out under pressure, which is practically the same as the pressure used to implement the above interesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid, however, this condition should not be considered as limiting object of the present invention. The pressure difference when the interesterification and dehydration is preferably less than 0.1 bar, particularly preferably less than 0.05 bar. According to a special variant of implementation of the present invention obtained gaseous (meth)acrylic acid may be used for transesterification without condensation and re-evaporation.

Dehydration of α-hydroxycarbonic acids are described, for example, in German patent application DE-A-1768253.

Obtained by dehydration of (meth)acrylic acid can again use the SQL for the synthesis of alkyl(meth)acrylates. In addition, (meth)acrylic acid is a commercial product. Thus, unexpectedly, it was found that the device for producing alkyl(meth)acrylates can also be used for the synthesis of (meth)acrylic acid, and the ratio between the obtained alkyl(meth)acrylates and (meth)acrylic acid can be easily adjusted by varying the concentration of water and/or temperature interesterification complex Olkiluoto ester of α-hydroxy-carboxylic acid.

Thus, the alkyl(meth)acrylates can be obtained from carbonyl compounds, hydrocyanic acid and alcohols simple and effective method comprising the following stages:

A) dealing at least one carbonyl compound with hydrocyanic acid with the formation of at least one cyanhydrin,

B) hydrolysis of cyanhydrin, respectively cyanhydrin, with the formation of at least one amide of an α-hydroxycarbonic acid,

C) alcoholysis amide α-hydroxycarbonic acid, respectively, amides of α-hydroxycarbonic acid, with the formation of at least one compound Olkiluoto ester α-hydroxycarbonic acid,

D) transesterification of complex Olkiluoto ester α-hydroxycarbonic acid, respectively complicated alilovic esters of α-hydroxycarbonic acid, (meth)acrylic acid with the formation, at m is re, one alkyl(meth)acrylate and at least one α-hydroxycarbonic acid,

E) dehydration of α-hydroxycarbonic acid, respectively α-hydroxycarbonic acids, with the formation of (meth)acrylic acid.

The present invention is illustrated in more detail in the following examples, including comparative examples.

Example 1

Shown in figure 2 of the reaction distillation column within 48 hours was introduced 4619 g complex methyl ester of α-hydroxyisovaleric acid (GIMM)and 3516 g of methacrylic acid (MAC). The interaction of the injected reagents was carried out at a temperature of 120°C and a pressure of 250 mbar. The resulting α-hydroxyisobutyryl acid out of the cube column. The methyl methacrylate (MMA) drove through the upper part of the column. The reaction was carried out in the presence of 16% wt. water in recalculation on weight of a complex of methyl ester of α-hydroxyisovaleric acid. Interesterification was carried out using an acidic catalyst (cation type Lewatit®K2431 company Voeg).

The selectivity, defined by the ratio of the number formed of methyl methacrylate (MMA) and α-hydroxyisovaleric acid (GIMC) to the number of transformed GIMM and POPPY, was 99%.

The selected α-hydroxyisobutyryl acid was subjected to dehydration in accordance with German patent application DE-OS 176853.

The resulting selectivity, determined by the ratio of the number of formed MMA to the number of transformed YMCM amounted to 98.5%.

Comparative example 1

The methyl methacrylate was obtained by dehydration complicated methyl ester of α-hydroxyisovaleric acid. Dehydration was carried out in accordance with European patent application EP-A-0941984. A mixture of 20 g of dihydrofolate sodium and 80 g of water was added to 60 g of silica gel. Under reduced pressure from the mixture was removed the water. The purpose of the preparation of the catalyst, the residue was dried overnight at 150°C. 10 g of the obtained catalyst were placed in a equipped with a quartz tube evaporator. A quartz tube was heated in a furnace, and the temperature of the catalyst layer was about 400°C. a Mixture of methanol with complex methyl ether, α-hydroxyisovaleric acid (2:1) was continuously evaporated at a rate of 10 grams per hour was passed through the catalyst bed. The selectivity of the reaction, determined by the ratio of the number of formed MMA to the number of transformed GIMM, was 88%.

Examples 2-18

Essentially repeating example 1, but water to the reaction mixture was added. The transesterification was carried out using indicated in table 1 conditions, primarily temperature, time and the molar ratio of doctow. Table 1 shows the selectivity interesterification, redeema the ratio of the number of generated MMA and GIMC to the number of transformed GIMM and MAC.

Table 1
ExamplesThe reaction temperature [°C]The molar ratio YMCM/POPPYThe residence time [min]Selectivity [%]
21201,0028,3393,21
3901,0042,5095,06
41001,0042,5094,81
51101,0042,5094,64
61201,0042,5090,67
7901,0085,0095,53
800 1,0085,0094,95
91101,0085,0093,55
101201,0085,0091,78
11901,00170,0094,83
121001,00170,0094,06
13902,042,5091,61
141002,042,5091,73
15902,085,0090,63
161002,085,0090,30
171200,5028,3392,05
181200,5042,5092,62

Examples 19-38

Essentially repeated the example 1, however, the transesterification was performed using indicated in table 2 conditions, primarily temperature and the residence time of the reagents. The molar ratio YMCM to MAC was 1:1. In addition, the amount of added water is varied in accordance with the table 2 data. In addition, table 2 shows the selectivity interesterification, defined by the ratio of the number of generated MMA and GIMC to the number of transformed GIMM and MACS, as well as the molar ratio GIMC to MMA.

Table 2
ExamplesThe reaction temperature [°C]The molar ratio of water to YMCMThe residence time [min]Selectivity [%]The molar ratio GIMC to MMA
199 0,2042,598,611,33
201000,2042,598,181,21
211100,2042,597,441,11
221200,2042,596,270,99
23900,208598.34 per1,18
241000,208597,661,09
251100,208596,561,02
261000,20 17096,951,00
27900,5042,598,801,61
281000,5042,598,641,36
291100,5042,5being equal to 98.21 per1,22
301200,5042,597,581,08
31900,508598,761,39
321000,508598,351,20
331100,5085of 97.78 1,10
341000,5017098,081.10
35901,0050,099,412,090
361001,0050,099,651,618
371101,0050,099,821,360
381201,0050,099,541,319

The above examples show that the formation of alkyl(meth)-acrylate in accordance with the present invention may occur with extremely high selectivity, and the ratio of alkyl(meth)-acrylates of α-hydroxycarbonic acid is close to unity and at relatively high concentrations of water. In accordance with this formed a relatively small amount of methane is La. When this molar ratio of the alkyl(meth)acrylates of α-hydroxycarbonic acid can also be adjusted by varying the temperature.

1. The method of obtaining the alkyl(meth)acrylates, including the state interesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid, followed by the formation of alkyl(meth)acrylate and α-hydroxycarbonic acid, and the stage of dehydration of α-hydroxycarbonic acid, followed by education (meth)acrylic acid.

2. The method according to claim 1, characterized in that the complex alkilany ether α-hydroxycarbonic acid is produced by alcoholysis amide hydroxycarbonate acid.

3. The method according to claim 2, characterized in that the amide hydroxycarbonate acid is produced by hydrolysis of cyanhydrin.

4. The method according to claim 3, characterized in that cyanhydrin is acetonecyanohydrin.

5. The method according to claim 3, characterized in that the hydrolysis using a catalyst.

6. The method according to claim 5, characterized in that the catalyst contains manganese oxide, sulfuric acid or an enzyme.

7. The method according to claim 2, characterized in that the alcohol used for the alcoholysis amide hydroxycarbonate acid contains from 1 to 10 carbon atoms.

8. The method according to claim 7, characterized in that the alcohol is methanol and/or ethanol.

9. The method according to claim 2, wherein the alcoholysis is carried out at a pace which the temperature from 160 to 240°C.

10. The method according to claim 2, characterized in that the United States carried out under a pressure of from 5 to 30 bar.

11. The method according to claim 2, characterized in that the United States use at least one alkaline catalyst.

12. The method according to claim 1, characterized in that the transesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid to catalyze the acid.

13. The method according to item 12, wherein the acid is an ion exchanger.

14. The method according to item 12, characterized in that the transesterification is carried out in a distillation column.

15. The method according to claim 1, characterized in that the transesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid is carried out under pressure from 100 mbar to 3 bar.

16. The method according to claim 1, characterized in that the transesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid is carried out at a temperature of from 70 to 130°C.

17. The method according to claim 1, characterized in that the transesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid is carried out in the presence of water.

18. The method according to 17, characterized in that the concentration of water is from 0.1 to 50 wt.% in terms of the mass of complex Olkiluoto ester α-hydroxycarbonic acid.

19. The method according to claim 1, characterized in that the molar ratio of the complex is th Olkiluoto ester α-hydroxycarbonic acid to (meth)acrylic acid with its transesterification with (meth)acrylic acid is from 3:1 to 1:3.

20. The method according to claim 1, characterized in that the response time for the interesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid is from 5 minutes to 5 hours

21. The method according to one of claims 1 to 20, characterized in that the dehydration of α-hydroxycarbonic acids and the transesterification complex Olkiluoto ester α-hydroxycarbonic acid (meth)acrylic acid is carried out at the same pressure.

22. The method according to one of claims 1 to 20, characterized in that the gaseous (meth)acrylic acid obtained by dehydration of α-hydroxycarbonic acid, sent for transesterification without condensation and re-evaporation.



 

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2 cl, 3 ex

FIELD: petroleum chemistry.

SUBSTANCE: invention can be implemented in rectifying and evaporating towers. Condenser 20 consists of tubular panel 33, of a dividing chamber 31, into which from above there is supplied gas containing acrylic acid, also the condenser consists of chamber 32 wherein cooling medium is supplied. Cooling pipes 34 vertically pass through chamber 32. The first pipe for supply of polymerisation inhibitor 28 enters chamber 31 outside condenser 20, while sprayer 35 is connected with the end of the first pipe for supply of polymerisation inhibitor 28. The first pipe for supply of polymerisation inhibitor 28 is supported with holder 36 outside condenser 20.

EFFECT: stable continuous processing in condenser during long period of time due to eliminating polymerisation of readily polymerised compound in condenser of simple design wherein fumes of readily polymerised compound enter.

5 cl, 2 ex, 6 dwg

FIELD: chemistry.

SUBSTANCE: invention concerns regeneration of monomer complex ethers of substituted or non-substituted acrylic acid or styrene-containing monomers, particularly device for regeneration of monomer complex ethers of substituted or non-substituted acrylic acid or styrene-containing monomers from polymer material containing respective structural units. Device includes: heated reactor for monomer-containing gas generation from polymer material, and shifting device for propulsion of relocated product, combined with reactor or being a part of reactor. To enhance output and purity of generated monomer, heat carrier comprised by multiple spherical units with diametre within 0.075 to 0.25 mm is preferred.

EFFECT: relocated material containing polymer material and heat carrier.

2 cl, 5 dwg, 3 ex

FIELD: chemistry.

SUBSTANCE: invention concerns organic compound synthesis, particularly method of obtaining 4-biphenylmetacrylate of the formula . Obtained compound is applied in production of heat and weather resistant polymer materials. Claimed method involves dissolution of 4-phenylphenol in 10 wt % aqueous solution of caustic soda, further dosage of acylating agent in the form of metacrylic acid anhydride agent in reaction mix preliminarily cooled to 0-(+5°)C at such rate so as to keep the mix temperature below +10°C at molar ratio of 4-phenylphenol and metacrylic acid anhydride of 1:(1.1-1.5), reaction mix maturing at room temperature with stirring, organic layer extraction, flushing by alkali solution, and drying.

EFFECT: enhanced output of 4-biphenylmetacrylate, admixture content of non-reacted 4-phenylphenol reduced to 0,003-0,005 wt %.

3 cl, 1 tbl, 10 ex

FIELD: chemistry.

SUBSTANCE: invention refers to advanced method of production of (meth)acrylic acid ester including (meth)acrylic acid purification by contacting raw (meth)acrylic acid containing manganese as an impurity manganese, and cation-exchange resin to remove manganese. To ensure contacting raw (meth)acrylic acid and cation-exchange resin, water is pre-added to (meth)acrylic acid. Besides, the method involves reaction of purified (meth)acrylic acid and alcohol with acid catalyst added.

EFFECT: method allows preventing effectively deactivation of the acid catalyst used in etherification reaction, equipment plugging and can ensure stable ester manufacturing.

3 cl, 5 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of obtaining (meth)acrylic ester including stage of etherification of (meth)acrylic acid with C1-C4alcohol in presence of catalyst from highly acidic cation-exchange resin in form of immovable layer for obtaining (meth)acrylic ester; addition of polymerisation inhibitor into reactor or into distillation column for isolation; stage of isolation, at which (meth)acrylic acid that did not react is separated from reaction solution, obtained at reaction stage, where temperature in distillation column still is in the range from 60 to 100°C, and pressure at the top of distillation column is in the range from 1.33 to 26.7 kPa; and recirculation stage in order to return thus obtained (meth)acrylic acid, that did not react, to reaction stage, where solid substances, contained in isolated (meth)acrylic acid that did not react and is returned to reaction stage, are isolated from it. In industry used method of obtaining (meth)acrylic esters is improved in such way as to prolong service life of used in it catalyst from highly acidic cation-exchange resin.

EFFECT: elaboration of improved method of obtaining (meth)acrylic ester.

5 cl, 2 ex, 1 dwg

FIELD: chemistry.

SUBSTANCE: present invention pertains to improvement of the method of producing (met)acrylic acid and complex (met)acrylic esters, involving the following stages: (A) reacting propane, propylene or isobutylene and/or (met)acrolein with molecular oxygen or with a gas, containing molecular oxygen through gas-phase catalytic oxidation, obtaining crude (met)acrylic acid; (B) purification of the obtained crude (met)acrylic acid, obtaining a (met)acrylic acid product; and (C) reacting raw (met)acrylic acid with alcohol, obtaining complex (met)acrylic esters, in the event that the installation used in any of the stages (B) and (C), taking place concurrently, stops. The obtained excess crude (met)acrylic acid is temporarily stored in a tank. After restoring operation of the stopped installation, the crude (met)acrylic acid, stored in the tank, is fed into the installation, used in stage (B), and/or into the installation used in stage (C). (Met)acrylic acid output of the installation used in stage (A) should be less than total consumption of (met)acrylic acid by installations used in stages (B) and (C).

EFFECT: the method allows for processing (met)acrylic acid, temporarily stored in a tank, when stage (B) or (C) stops, without considerable change in workload in stage (A).

2 ex

FIELD: chemistry.

SUBSTANCE: invention pertains to the chemistry of organic compounds, and specifically to the method of obtaining 1,1,3-trihydroperfluoropropyl esters s-aminocapronic acid, which can be used in polymer compositions and exercise a significant influence on improving physical and mechanical properties of the obtained materials. Besides that, in conjunction with phosphorous-organic components they can be used for making compositions with low combustibility. The essence lies in that the method of obtaining 1,1,3-trihydroperfluoropropyl esters of ε-aminocapronic acid with formula HCF2CF2CH2O[C(O)(CH2)5NH]nH (n=1, 2) involves reaction of ε-caprolactam and 1,1,3-trihydroperfluoropropanol in the presence of a catalyst. The used catalyst is diacetate-N-(1,3,2-dioxophospholanyl)-ε-copper caprolactamate with formula . The process is carried out at molar ratio of reagents and catalyst equal to 1:(1-2):(0.05-0.1), at 150-170°C for a period of 0.5-1 hour with subsequent separation of the mixture of ethyl alcohol.

EFFECT: simplification of the process of obtaining low molecular products from ε-caprolactam and "ПФС1", as well as obtaining esters not previously described with number of monomer links equal to 1 and 2.

1 cl, 1 ex, 1 tbl

FIELD: chemistry.

SUBSTANCE: invention concerns organic compound synthesis, particularly method of obtaining 4-biphenylmetacrylate of the formula . Obtained compound is applied in production of heat and weather resistant polymer materials. Claimed method involves dissolution of 4-phenylphenol in 10 wt % aqueous solution of caustic soda, further dosage of acylating agent in the form of metacrylic acid anhydride agent in reaction mix preliminarily cooled to 0-(+5°)C at such rate so as to keep the mix temperature below +10°C at molar ratio of 4-phenylphenol and metacrylic acid anhydride of 1:(1.1-1.5), reaction mix maturing at room temperature with stirring, organic layer extraction, flushing by alkali solution, and drying.

EFFECT: enhanced output of 4-biphenylmetacrylate, admixture content of non-reacted 4-phenylphenol reduced to 0,003-0,005 wt %.

3 cl, 1 tbl, 10 ex

How prelinlinary // 2051143

FIELD: process engineering.

SUBSTANCE: invention can be used for filling the reactor with poly element oxide catalyst. Catalyst particles are prepared that contain substance liquid at 20°C and 1 atm, substance content varying from 0.05 to 10% by weight. Reactor is filled with catalyst particles fed through hole made in reactor top section, said particles being lowered inside the reactor by gravity.

EFFECT: efficient loading of catalyst into reactor with small-diametre tubes for catalysed vapor-phase reactions, ruling out of catalyst attrition.

1 tbl, 4 ex, 28 cl

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