HK1202523B - Transvinylation as a first stage of coupling production of vinyl esters and acetic acid or propionic acid reaction products - Google Patents

Abstract

The invention relates to a method for the coupling production of acetic acid or propionic acid reaction products and a vinyl ester of formula R-C(O)O-CH = CH2 by a transvinylation reaction of a carboxylic acid of formula R-C(O)OH with a transvinylation reagent of formula R1-C(O)O-CH = CH2 wherein R represents an aliphatic, cycloaliphatic or aromatic radical and R1 is methyl or ethyl and the transvinylation reaction is continuously carried out without removing a reaction partner in the presence of a transition metal catalyst containing at least one transition metal selected from the group comprising ruthenium, osmium, rhodium, iridium, palladium and platinum, the obtained reaction mixture being separated from its components, the vinyl ester of formula R-C(O)O-CH = CH2 and the carboxylic acid of formula R1-C(O)-OH being separated and the thus obtained carboxylic acid R1-C(O)-OH being converted into a derivative of formula R1-C(O)-X, R1-CH2-OH or R6-C(O)-OH.

Description

Transvinylation as a first stage for the co-production of vinyl ester and acetic or propionic acid reaction products

The invention relates to a method for the combined production of vinyl esters by continuously carrying out the vinylation reaction of a carboxylic acid with vinyl acetate or vinyl propionate, and to the combined production of a conversion product made from the acetic acid or propionic acid formed.

The higher vinyl carboxylates have certain economic significance as comonomers. It can be used to modify the properties of polymers such as polyvinyl chloride, polyvinyl acetate, polystyrene or polyacrylates. For example, the hydrolysis resistance of emulsion paints can be increased. For the production of the adhesives, vinyl esters of higher carboxylic acids are likewise used. For these fields of use, vinyl esters based on 2-ethylhexanoic Acid, isononanoic Acid, dodecanoic Acid or Versatic acids 911, 10 and 1519 from Shell (Shell) have been found to be of industrial interest. These higher carboxylic acids can be obtained, for example, by oxidation of aldehydes prepared by oxo reaction or by the so-called Koch synthesis (Koch synthesis) of olefins, carbon monoxide and water. In the case of vinyl esters based on 2-ethylhexanoic Acid, dodecanoic Acid or isononanoic Acid, the compound is homogeneous if isononanoic Acid consists predominantly of 3,5, 5-trimethylhexanoic Acid, whereas in the case of vinyl esters of Versatic Acid 911 a mixture of highly branched carboxylic acids having from 9 to 11 carbon atoms is incorporated within the vinyl ester, and in the case of vinyl esters of Versatic Acid 1519 a mixture of highly branched carboxylic acids having from 15 to 19 carbon atoms is incorporated within the vinyl ester. In the case of the vinyl ester of Versatic Acid 10, a structurally different highly branched decanoic Acid, such as neodecanoic Acid, is derivatized. On an industrial scalePreparation of 3,5, 5-trimethylhexanoic acid by hydroformylation of diisobutylene and subsequent oxidation of the corresponding aldehyde (Ullmanns)der technischen Chemie (Ullmanns encyclopedia of chemical engineering), 4^thedition,1983,Verlag Chemie,Volume 9,pages 143-145；Volume 23,pages606-607)。

It is known that vinyl carboxylates can be prepared by reaction of acetylene with carboxylic acids (G.H ü bner, Fette, Seifen, Anthrichmitel 68,290 (1966)), Ullmannsdertechnischen Chemie,4^thedition,1983, Verlag Chemie, Volume23, pages 606-607). This procedure is employed in EP1057525A2, according to which gaseous acetylene is reacted with the carboxylic acid to be vinylated in the presence of a catalyst in a tubular reactor. In the known heterogeneous processes, the carboxylic acid containing the catalyst, for example a zinc salt, in dissolved form constitutes the continuous phase, with gaseous acetylene being present as the dispersed phase. The tubular reactor is operated at a load factor greater than 0.8. However, the use of acetylene as a raw material on an industrial scale requires a high level of equipment and safety complexity (aufwind), and furthermore acetylene is generally only available locally.

It is also known that vinyl carboxylates can be prepared by so-called transvinylation reaction with another vinyl carboxylate:

wherein R and R¹Each may be an aliphatic or aromatic group. To control the equilibrium reaction in the product direction, a high excess of the vinylating reagent R is often used¹-C(O)O-CH＝CH₂. Formed carboxylic acid R¹the-C (O) OH should also be sufficiently volatile to allow rapid removal from equilibrium and thus allow for increased conversion. Since the reaction mixture is generally worked up by distillationCompounds, and thus the vinylating reagent R is often directed by the boiling point of the other reaction participants¹-C(O)O-CH＝CH₂Selection of (Ullmanns)der technischen Chemie,4^thedition,1983, VerlagChemie, Volume23, pages 606-607). For the preparation of higher vinyl carboxylates, in particular vinyl acetate and to some extent vinyl propionate are suitable as vinylating agents. The chemical vinyl acetate produced on an industrial scale is available inexpensively. Vinyl acetate and the acetic acid formed therefrom have relatively low boiling points and can be separated from the desired vinyl ester of a higher carboxylic acid by distillation.

There are many suggestions in the literature regarding the trans-vinylation reaction of carboxylic acids with vinyl acetate as vinylating agent. Adelman (Adelman, Journal of Organic Chemistry,1949,14, pages1057-1077) investigated the transvinylation of higher carboxylic acids such as stearic acid, dodecanoic acid or 3,5, 5-trimethylhexanoic acid with vinyl acetate in the presence of mercury salts as catalysts. US2245131 discusses the reaction of benzoic acid or crotonic acid with vinyl acetate in the presence of mercury acetate. The reaction mixture was first kept under reflux. Thereafter, the reaction temperature is raised and the acetic acid formed is removed. The vinyl benzoate formed is then purified by further fractional distillation. US2299862 discloses the preparation of vinyl 2-ethylhexanoate from 2-ethylhexanoic acid and vinyl acetate in the presence of mercury acetate and sulfuric acid. The resulting crude mixture was first neutralized with sodium acetate and then distilled. Vinyl 2-ethylhexanoate was obtained in a yield of 73%. According to DE1222493B, the catalyst for the vinylation reaction using vinyl acetate is the mercury salt of a sulfonic acid cation exchange resin.

Disadvantages of the vinylation process using mercury-containing catalysts are their toxicity and volatility and the formation of undesirable ethylene diesters. The activation with sulfuric acid as a rule and the need to deactivate the catalyst by neutralization before distillation of the reaction mixture also imply an additional process step.

By using palladium catalysts can be avoidedThese disadvantages, in this case, have found to be advantageous for modifying the palladium complex with aromatic nitrogen-containing ligands, for example with 2,2' -bipyridine or 1, 10-phenanthroline. According to US 5214172, the activity of a palladium catalyst modified in this way is increased by the addition of a strong acid. US 5741925 discusses the trans-vinylation of naphthenic acids in the presence of palladium complexes modified with 2,2' -bipyridine or 1, 10-phenanthroline. According to a known procedure, naphthenic acids, preferably cyclic C, are cyclized under reflux using vinyl acetate as the vinylating reagent₁₀-C₂₀The carboxylic acid is converted to the corresponding vinyl ester. During the distillation, the catalyst is stable and can be reused several times. The process disclosed by US 5223621 involves the vinylation of carboxylic acids such as dodecanoic acid or benzoic acid with an in situ formed palladium (II) 2,2' -bipyridine diacetate complex at reflux. Before distilling the crude product, the catalyst is precipitated with oxalic acid or hydrochloric acid and removed by filtration. The use of combined catalyst systems consisting of palladium salts and redox agents for the trans-vinylation of carboxylic acids is also known. EP 0376075a2 recommends redox-active catalyst systems consisting of palladium chloride, copper (II) bromide and lithium acetate. By way of example, the batch-wise vinylation of dodecanoic acid with vinyl acetate having a boiling point close to that of vinyl acetate is described. The pure desired vinyl ester is obtained in a subsequent distillation. Another configuration (configuration) of redox-active catalyst systems is disclosed in JP2002-322125 a. It involves heating a reaction mixture consisting of carboxylic acid and vinyl acetate and palladium and lithium acetate to 65 ℃.

The prior art also mentions the use of ruthenium-containing catalysts for the vinylation reaction. According to Murray (Murray, Catalysis Today1992,13, pages93-102), metallic ruthenium or ruthenium compounds, e.g. ruthenium chloride, ruthenium oxide or ruthenium carbonyls, e.g. Ru₃(CO)₁₂When present, higher carboxylic acids such as 2-ethylhexanoic acid, benzoic acid, neodecanoic acid, neononanoic acid or adipic acid can be converted to the corresponding vinyl esters with vinyl acetate. The reaction is carried out batchwise under carbon monoxide or nitrogen at a pressure of about 2 bar (bar) and a temperature of typically 130-150 ℃. Corresponding processes are likewise known from EP 0351603A2 and EP 0506070A2. It is noted that ruthenium catalysts are more thermally stable than palladium catalysts, which deactivate and deposit metallic palladium at elevated temperatures. However, in the known ruthenium-catalyzed processes, only moderate yields have been reported. Most of the trans-vinylation processes described in the prior art are usually carried out batchwise at reflux and occasionally under pressure in closed reaction vessels.

A continuously operated vinylation process is known from EP 0497340A 2. By means of continuously operated reactive distillation, the vinylation reaction R-C (O) OH + R is carried out by continuously removing the most volatile reaction components¹-C(O)O-CH＝CH₂→R¹-C(O)OH+R-C(O)O-CH＝CH₂The equilibrium of (a) is shifted towards the product. Selective vinylation reagent R¹-C(O)O-CH＝CH₂So that the corresponding acid R¹C (O) OH is volatilized and removed from the equilibrium. The process according to EP 0497340a2 preferably uses vinyl acetate as the vinylating agent and the acetic acid formed is removed from the reaction zone together with unreacted vinyl acetate. Thereafter, vinyl acetate separated from the acetic acid in the separation step is returned to the reaction zone. Known processes use ruthenium catalysts such as [ Ru (CO ]₂OAc]_nAnd describes the transcthylenization of adipic acid, neodecanoic acid, and 2-ethylhexanoic acid. However, in order to suppress the formation of undesired anhydrides, it is only carried out until partial conversion of the desired vinyl ester.

WO2011/139360a1 and WO2011/139361a1 disclose processes for the continuous and semi-continuous vinylation of vinyl acetate with carboxylic acids using palladium complexes containing aromatic nitrogen-containing ligands such as 2,2' -bipyridine and 1, 10-phenanthroline. The continuous process is carried out in a bubble column connected with a packed column, and a rectifying column and a stripping column can be additionally connected at the downstream of the bubble column. Vinyl acetate is introduced into the bubble column while a mixture of carboxylic acid and vinyl acetate containing the catalyst in dissolved form is introduced into the connected packed column. The carboxylic acid and catalyst flow into the bubble column, while the vinyl acetate flows countercurrently through the bubble column and the attached packed column. Vinyl acetate and acetic acid formed are removed and separated in downstream rectification and stripping columns.

It is also known from the prior art to enrich the acetic acid released in the vinylation reaction using vinyl acetate in order to obtain a mixture with a high proportion of acetic acid and to use it together with the remaining amount of vinyl acetate present during the preparation of vinyl acetate (abstracts of WO2011/139360a1, WO2011/139361a1, JP 2002322127). The processing of the reaction mixture into pure acetic acid and its use for subsequent derivatization procedures are also mentioned. The prior art does mention the production of conversion products using acetic acid liberated in the vinylacetate conversion reaction, but for continuous processes in which the vinylacetate, the conversion reagent, is not used efficiently for the production of vinyl esters, it is no longer usable for the vinylation reaction because it evaporates after a very short residence time due to the reaction conditions chosen. Furthermore, the known continuously carried out vinylation processes are complicated to use with apparatuses and their design entails high investment costs, since a series of columns as additional reaction columns must be connected downstream of the reaction vessel. The known processes therefore allow only moderate space-time yields of the desired vinyl esters.

There is therefore a need for a process for the co-production of vinyl acetate and acetic acid conversion products or propionic acid conversion products in which the vinylation reaction of a carboxylic acid with vinyl acetate or propionate is carried out continuously and in which a low level of plant complexity ensures a high space-time yield of the desired vinyl ester, i.e. a high product output per unit reaction volume and time. Likewise, the desired vinyl esters can be obtained with high selectivity. Acetic or propionic acids with high space-time yields and selectivities can also be obtained in a continuous process, thereby improving the economic viability of downstream derivatization processes.

The invention therefore comprises the reaction of a carboxylic acid of the formula R-C (O) OH with a compound of the formula R¹-C(O)O-CH＝CH₂Co-production of a transvinylation reaction of a transvinylation reagent of the formula R-C (O) O-CH ═ CH₂The vinyl ester method of (a):

R-C(O)OH+R¹-C(O)O-CH＝CH₂→R¹-C(O)OH+R-C(O)O-CH＝CH₂

whereinR is an aliphatic, cycloaliphatic or aromatic radical, R is¹Is methyl or ethyl and coproduced to the carboxylic acid R derived from the formation¹Formula R of-C (O) -OH¹Derivatives of (a) c (O) -X, wherein X is ethyleneoxy O-CH ═ CH₂Halogen of the formula OR²Alkoxy of (2), wherein R²Is a substituted or unsubstituted hydrocarbon radical having from 1 to 10 carbon atoms, of the formula NR³R⁴Wherein R is³And R⁴Each independently hydrogen or a substituted or unsubstituted hydrocarbyl group having 1 to 10 carbon atoms, or of the formula O-C (O) -R⁵Wherein R is⁵Is hydrogen or a substituted or unsubstituted hydrocarbyl group having 1 to 10 carbon atoms; or produced in combination to produce the formula R¹-CH₂-a derivative of-OH; or produced in combination to produce the formula R⁶Derivatives of-C (O) -OH, wherein R⁶Is R partially or fully substituted by halogen¹The method is characterized in that:

(a) the transvinylation reaction is continuously carried out in the presence of a transition metal catalyst containing at least one transition metal selected from ruthenium, osmium, rhodium, iridium, palladium and platinum without taking out the reactants;

(b) separating the resulting reaction mixture into its components and removing the compound of formula R-C (O) O-CH ═ CH₂Vinyl esters of the formula R¹-C (O) -OH; and

(c) converting the carboxylic acid obtained after step b into the formula R¹-C(O)-X、R¹-CH₂-OH or R⁶-C (O) -OH derivatives.

In contrast to known continuous processes, in which at least one reactant is continuously withdrawn from the vinylation equilibrium and thus the chemical equilibrium is continuously destroyed, the reaction in the process of the invention can be carried out in a steady state without withdrawing a reactant. The reaction system is in a stable state and the mixture withdrawn from the reaction vessel is not separated into its components until later processing. In the presence of a transition metal catalyst, carboxylic acid R-C (O) OH and a vinylation reagent R are reacted¹-C(O)O-CH＝CH₂And which is generally at 20-160 deg.CPreferably at a temperature of from 60 to 150 c, especially from 90 to 140 c. The process according to the invention surprisingly achieves high yields and high space-time yields of the desired vinyl esters even when operated without removal of reactants.

The conversion to ethylene can be carried out at standard pressure or elevated pressure, generally up to 15MPa, preferably from 0.5 to 8MPa, in particular from 0.8 to 2 MPa. A particularly suitable reaction setting has been found to be a temperature of from 90 to 140 ℃ and a pressure of from 0.8 to 2 MPa. Surprisingly, however, very high space-time yields of the desired vinyl esters are likewise achieved, even at standard pressures and reaction temperatures of, in particular, from 60 to 150 ℃.

Suitable reaction vessels are tubular reactors, such as flow tubes in any arrangement, for example vertical or horizontal flow tubes or multiple coiled flow tubes. The tubular reactor can be operated as an empty tube, but it can likewise contain loose packings or internals, such as Raschig rings (Raschig ring), saddles (saddle), pall rings (Pallring), spirals, baffles or static mixers or mixer packings. Static mixing elements are commercially available and can be supplied as, for example, Sulzer mixers (Sulzer mixers) or Kenicks mixers with special production lines for mixing liquids of different viscosities. The tubular reactor may also be provided with a circulation pump and optionally a heat exchanger.

During operation of the tubular reactor, the starting carboxylic acid R-C (O) OH and the vinylating reagent R can be separately but simultaneously reacted¹-C(O)O-CH＝CH₂Introduced into the tubular reactor in a co-current or counter-current direction. It is also possible to mix the two liquids beforehand and introduce them as a homogeneous solution into the tubular reactor. In particular embodiments, the homogeneous solution flows through an upstream static mixing element prior to entering the tubular reactor.

The vinylation reaction can likewise be carried out continuously in stirred tanks or in cascade-stirred tanks at ambient pressure or under pressure. The raw material carboxylic acid R-C (O) OH and a conversion vinylating reagent R¹-C(O)O-CH＝CH₂The feeds are continuous, either separately or as a mixture, and the reaction mixture is continuously removed in steady state. Can also be atThe reaction is carried out continuously in reactor designs conventional in the art, such as in a loop reactor or multi-chamber reactor utilizing thermal convection. The reaction vessel can also be configured as a cylindrical reactor with axially arranged nozzles for introducing the starting carboxylic acids R-C (O) OH and the vinylating reagent R¹-C(O)O-CH＝CH₂Further comprising axially arranged conduits for generating an internal forced flow.

It has been found that the advantageous reaction vessel space velocity V/Vh of the mixture of the conversion vinylating reagent and the previously prepared starting carboxylic acid to be vinylated is in the range from 0.4 to 7.0h, based on the reactor volume and time^-1Preferably 0.7-6.2h^-1. If the two reactants are introduced into the reaction vessel separately but simultaneously, the space velocity V/Vh of the reaction vessel for the vinylating reagent is in each case from 0.2 to 6.0h, based on the reactor volume and time^-1The space velocity V/Vh of the reaction vessel for the starting carboxylic acid is from 0.1 to 6.7h, based on the reactor volume and time^-1。

By virtue of the embodiment of the continuous process which is carried out in the steady state, very high space-time yields are advantageously achieved in comparison with the known reactive distillation in which the carboxylic acid formed is removed continuously from the reaction system together with the vinylating reagent. The process variant additionally requires a high input of the vinylating reagent, so that a sufficiently high concentration in the reaction mixture and in order to provide a sufficient loading of the reactive distillation column are constantly ensured, and a high recycling rate of the vinylating reagent is necessary. The known continuous reaction schemes require high reactor volumes and a high level of plant complexity. Consequently, only moderate space-time yields can be achieved with a relatively high level of plant complexity in combination with high investment costs.

To avoid side reactions such as the polymerization of vinyl esters, suitable inhibitors such as hydroquinone, methoxy hydroquinone, t-butyl catechol or phenothiazine may be added to the ethylene-converting reagent prior to entry into the reaction vessel. However, it is also possible to introduce the inhibitors into the reaction vessel separately and continuously. The inhibitor concentration in the homogeneous reaction mixture is generally from 3 to 150ppm, based on the amount of vinylating agent used.

Suitable starting carboxylic acids R-C (O) OH which can be converted into the corresponding vinyl esters by the process of the present invention are aliphatic, cycloaliphatic or aromatic carboxylic acids. The organic R groups generally contain from 2 to 20, preferably from 4 to 13, carbon atoms. The aliphatic carboxylic Acid includes, for example, propionic Acid, n-butyric Acid, isobutyric Acid, n-valeric Acid, 2-methylbutyric Acid, 3-methylbutyric Acid, pivalic Acid, n-heptanoic Acid, 2-methylhexanoic Acid, 2-ethylhexanoic Acid, n-octanoic Acid, n-nonanoic Acid, isononanoic Acid, neononanoic Acid, n-decanoic Acid, 2-propylheptanoic Acid, neodecanoic Acid or Versatic Acid 10, Versatic Acid 911, Versatic Acid 1519, dodecanoic Acid, tridecanoic Acid, palmitic Acid or stearic Acid. Among the various isononanoic acids which can be converted to ethylene by the process of the invention, 3,5, 5-trimethylhexanoic acid is particularly suitable, which can be obtained by hydroformylation of diisobutylene to the corresponding 3,5, 5-trimethylhexanoic aldehyde followed by oxidation. If diisobutylene is reacted with carbon monoxide and water in the presence of a strongly acidic catalyst, 2,4, 4-tetramethylpentanoic acid, also known as neononanoic acid, is predominantly obtained. Pivalic Acid, neononanoic Acid, neodecanoic Acid or Versatic Acid 10 or Versatic Acid 911, mixtures of isomeric C9 to C11 carboxylic acids and Versatic Acid 1519, mixtures of isomeric C15 to C19 carboxylic acids are highly branched carboxylic acids which carry 3 alkyl groups on the carbon atom adjacent to the carboxyl group and have the so-called neo structure. Despite the high branching close to the carboxyl group, these neo-acids can also be converted into the corresponding vinyl esters in good yields. Versatic Acid is the brand name of shell.

In addition, it is also possible to convert aromatic carboxylic acids, such as benzoic acid or naphthalene carboxylic acids, or unsaturated aliphatic carboxylic acids, such as acrylic acid, crotonic acid or methacrylic acid, into vinyl derivatives. Liquid carboxylic acids can be used directly in the process of the present invention. The solid carboxylic acid is dissolved in a solvent such as toluene, THF, dioxane or a cyclic ether, or directly in a transvinylating reagent and used as a solution in the transvinylation reaction.

The vinylation reagent R used¹-C(O)O-CH＝CH₂Is R¹Vinyl acetate being methyl, or R¹Being ethylVinyl propionate. In particular, vinyl acetate is considered to be an advantageous vinylating reagent due to its low cost availability. Vinyl acetate or propionate is generally used in a molar excess of up to 10:1, preferably up to 5:1, based on the molar carboxylic acid input R-C (O) -OH. The reaction mixture removed from the reaction vessel is usually worked up by distillation. Excess unreacted vinyl acetate or vinyl propionate, the acetic acid or propionic acid formed and the desired vinyl ester are removed as volatile components and separated off further. In the residue, the starting carboxylic acid together with the catalyst for the vinylation is left. Optionally after addition of fresh catalyst, the catalyst-containing residue is recycled back to the vinylation reaction after optionally removing a secondary stream containing high boilers. Vinyl acetate or vinyl propionate can likewise be used in molar deficit amounts of as low as 0.1:1, preferably as low as 0.2:1, based on the molar carboxylic acid input. This reduces the complexity of removing vinyl acetate or vinyl propionate. It has been found to be likewise advantageous to add inhibitors such as hydroquinone, methoxyhydroquinone, tert-butylcatechol or phenothiazine during the working up of the reaction mixture and the further purification of the desired vinyl esters.

The vinylation catalysts used are complexes of the platinum group transition metals ruthenium, osmium, rhodium, iridium, palladium and platinum, which have been modified with monodentate or multidentate organic nitrogen or organic phosphorus ligands. If mixtures thereof are used, based on the starting compounds used in each case in deficit, i.e. based on the carboxylic acid R-C (O) OH used or on the vinylating reagent R used¹-C(O)O-CH＝CH₂The total concentration of transition metals is generally from 0.005 to 1.5 mol%, preferably from 0.01 to 1.0 mol%, in particular from 0.02 to 0.6 mol%. Even though transition metal-ligand complexes of stoichiometric composition may be used as catalysts, they are usually processed in the presence of an excess of ligand (i.e., ligand that has not yet become a complex bound to the transition metal). For each mole of transition metal, 1 to 40mol, preferably 3 to 30mol, of ligand are used. Particularly advantageous molar ratios of transition metal to ligand have been found to range from 1:3 to 1: 10.

Suitable monodentate organic nitrogen ligands are, for example, pyridine, quinoline, picoline positional isomers, lutidine positional isomers, collidine, aniline, methylaniline positional isomers, dimethylaniline positional isomers, N-methylaniline, or aliphatic and aromatic amides such as N, N-dimethylformamide, acetanilide or N-methyl-2-pyrrolidone; suitable monodentate organophosphorus ligands are, for example, trialkylphosphines such as tributylphosphine or trioctylphosphine, triarylphosphines such as triphenylphosphine or tritolylphosphine, tricycloalkylphosphines such as tricyclohexylphosphine, alkylarylphosphines such as monobutyldiphenylphosphine or dipropylphenylphosphine, cycloalkylarylphosphines, trialkylphosphites or triarylphosphites such as triphenyl phosphite or trinaphthyl phosphite. Suitable multidentate organic nitrogen or organic phosphine ligands are, for example, bidentate ligands such as 2,2 '-bipyridine, 1, 10-phenanthroline, N, N, N', N '-tetramethylethylenediamine, P, P, P', P '-tetraphenyl-1, 2-diphosphinoethane, 4, 7-diphenyl-1, 10-phenanthroline, 5-chloro-1, 10-phenanthroline, 3,4,7, 8-tetramethyl-1, 10-phenanthroline, 2,9,4, 7-tetramethyl-1, 10-phenanthroline, 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline, 2, 9-dimethyl-1, 10-phenanthroline, 4' -diphenyl-2, 2 '-bipyridine, 4-methyl-1, 10-phenanthroline, 2' -biquinoline or 5-methyl-1, 10-phenanthroline.

The transition metal-ligand complex need not be a homogeneous composition, but may consist of, for example, a mixture of transition metal-ligand complexes differing in ligand nature and/or transition metal nature. It is also possible for the free ligands present in the organic solution to consist of a mixture of different monodentate or multidentate organic nitrogen or organic phosphine ligands. Typically, the conversion vinylation catalyst is formed from a transition metal, a transition metal compound or a corresponding mixture and a monodentate or multidentate organic nitrogen ligand, an organic phosphine ligand or a corresponding mixture in a reaction mixture under conversion ethylene reaction conditions.

The trans-vinylation catalyst can also be prepared separately in a pre-formation reaction. Suitable solvents for carrying out the preformation may be the vinylating agent, the starting carboxylic acid to be vinylated or mixtures thereof. The conditions of the preformation step generally correspond to those of the trans-vinylation reaction. The preformation conditions can be determined at the beginning of the vinylation process, so that the vinylation reagent and the starting carboxylic acid to be vinylated do not enter the reaction vessel until an active vinylation catalyst has formed in the initially fed organic solution. If the transition metal-ligand complex catalyst is added during operation, the active transition metal-ligand complex catalyst solution must first be prepared in a separate pre-formation step and then added to the process as a new solution. In this case, the solvent used in the preformation step is the trans-vinylating agent, the starting carboxylic acid to be vinylated or a mixture thereof.

In the preformation step, the ligand may also be used in excess, thereby establishing the above-described transition metal to ligand molar ratio during the transcthylenation reaction.

The vinylation catalyst used may also be an unmodified transition metal complex containing at least one transition metal selected from ruthenium, osmium, rhodium, iridium, palladium and platinum, which does not carry any monodentate or multidentate organic nitrogen or organic phosphine ligands. It may be assumed that under the conditions of the vinylation reaction, an active transition metal complex is formed from the catalyst precursor used, such as a transition metal or a carbonyl compound, carboxylate, halide or acetylacetonate of the transition metal. In case an unmodified transition metal complex is used, carbon monoxide is optionally added. In particular, the use of the unmodified form of the ruthenium catalyst.

In the case of the use of unmodified transition metal complexes, it has been found to be advantageous to add redox-active transition metals of group Ib of the periodic Table of the elements and alkali metal compounds. An example of a suitable redox active transition metal is copper in the form of a divalent copper halide. The alkali metal compound used is preferably a lithium compound, for example a lithium carboxylate such as lithium acetate or propionate, lithium carbonate, lithium bicarbonate, lithium chloride or lithium hydroxide. Suitable vinylation catalysts can be formed from, for example, palladium chloride, copper (II) bromide, and lithium acetate precursors. An active vinylation catalyst is formed from a suitable precursor under reaction conditions in a reaction vessel. The pre-formation of the catalyst can be carried out either initially in the reaction vessel or in a separate vessel.

The platinum group transition metals used are in metallic form or in the form of compounds. In metallic form, it can be used in the form of finely divided particles or precipitated as a thin layer on a support such as activated carbon, calcium carbonate, aluminum silicate, alumina. Suitable transition metal compounds are the salts of the starting carboxylic acids to be vinylated or the salts of the corresponding carboxylic acids formed, for example the acetates, propionates, butyrates, 2-ethylhexanoates or isononanoates. Inorganic hydrogen-containing or oxygen-containing acids such as nitrates or sulfates, various oxides or carbonyl compounds or complexes such as cyclooctadiene-based compounds or acetylacetonates can also be used. Although transition metal-halogen compounds are useful, corrosion behavior due to halide ions is not very useful.

Preference is given to using palladium or ruthenium compounds, in particular the acetates, propionates, butyrates, 2-ethylhexanoates, isononanoates, acetylacetonates, triflates, trifluoroacetates or carbonyl compounds thereof, e.g. Ru₃(CO)₁₂、H₄Ru₄(CO)₁₂Or [ Ru (CO)₂OAc]_n。

If the vinylation reaction has been carried out under pressure, the liquid output of the reaction vessel is subsequently depressurized to standard pressure via a depressurization stage and worked up in a further separation apparatus. It has also been found to be convenient to first cool the liquid reaction output to a temperature such that the formation of gaseous products is reduced in the depressurisation stage. Any gaseous components formed are removed and the resulting liquid phase is further processed, suitably by distillation. In the subsequent distillation, vinyl acetate or vinyl propionate, the acetic acid or propionic acid formed and the desired vinyl esters are separated as volatile constituents from the virtually non-volatile unconverted starting carboxylic acid comprising the catalyst for the vinylation. The volatile components removed are subsequently separated into vinyl acetate or propionate, acetic acid or propionic acid and the desired vinyl esters. The vinyl acetate or vinyl propionate is recycled to the reaction vessel as a transvinylating agent, removing a product stream rich in acetic acid or propionic acid, and further purifying the desired vinyl ester. The feed carboxylic acid containing high boiling catalyst is recycled as a catalyst recycle stream. In the particular case of the reaction of acetic acid with vinyl propionate to form vinyl acetate and propionic acid, the propionic acid formed is obtained as a less volatile component and in which a transvinylation catalyst is present. In this case, a portion of the propionic acid is removed from the catalyst-containing residue.

Optionally, a secondary stream containing high boilers is withdrawn from the catalyst loop and fresh catalyst, optionally in preformed form, or simply fresh ligand is added.

Subsequently further purifying the product stream enriched in acetic acid or propionic acid and converting the acetic acid or propionic acid produced to the general formula R¹-C (O) -X derivatives, wherein R¹Is methyl or ethyl.

X is ethyleneoxy O-CH ═ CH₂Halogen of the formula OR²Alkoxy of (2), wherein R²Is a substituted or unsubstituted hydrocarbon radical having 1 to 10 carbon atoms, preferably an alkyl radical, of the formula NR³R⁴Wherein R is³And R⁴Each independently of the others, hydrogen or a substituted or unsubstituted hydrocarbon radical having from 1 to 10 carbon atoms, preferably an alkyl radical, or of the formula O-C (O) -R⁵Wherein R is⁵Is hydrogen or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, preferably an alkyl group.

Where X is vinyloxy O-CH ═ CH₂In the case of (b), acetic acid or propionic acid is derived as vinyl acetate or vinyl propionate. The reaction of acetic acid or propionic acid with ethylene and oxygen to give vinyl acetate or vinyl propionate is known per se and is usually carried out in the gas phase using a solid supported palladium catalyst which additionally contains a promoter such as cadmium or gold. Vinyl acetate or vinyl propionate may be used as a re-vinylating agent. Vinyl acetate or propionate, however, is of special industrial interest for the preparation of polyvinyl acetate and copolymers thereof with ethylene or vinyl chloride (Ullmanns)dertechnischen Chemie,4^thedition,1983,Verlag Chemie GmbH,Volume 23,pages 601-605)。

If X is a halogen, for example chlorine, bromine or iodine, the corresponding acid halide is obtained. Formation of acid chlorides by reaction of acetic acid or propionic acid with standard chlorinating agents such as phosphorus trichloride, phosgene or sulfuryl chloride (Ullmanns)der technischen Chemie,4^thedition,1983, VerlagChemie GmbH, Volume 11, page 71; volume 19, page 457) and is important as a reaction intermediate for the formation of more complex compounds.

In which X is alkoxy OR²In the case of (b), an acetate or propionate is then obtained, which is of economic interest as a solvent for paints and resins. More particularly, suitable esters are those wherein R is²Denotes esters of alkyl groups having 1 to 4 carbon atoms, such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate or isobutyl acetate or the corresponding propionic acid esters. Acetic acid or propionic acid is generally esterified with a suitable alcohol in the presence of an acidic catalyst and with removal of the water formed by the reaction and is known per se (Ullmanns)der technischen Chemie,4^thedition,1983,Verlag Chemie GmbH,Volume 11,pages 68-70；Volume 19,pages457-458)。

When X is an amino group NR³R⁴Then an amide is obtained, in particular R³And R⁴Independently of one another, are amides of hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, which are industrially relevant as intermediates for the further synthesis. Obtained by reaction of an acetate or propionate with ammonia or a suitable amide, the preparation being known per se (Ullmanns)dertechnischen Chemie,4^thedition,1983,Verlag Chemie GmbH,Volume 11,page 71)。

If X is a carboxyl group O-C (O) -R⁵Then, an acid anhydride is obtained. If R is¹And R⁵Each being a methyl group, acetic anhydride is obtained which can be prepared industrially by dehydration of acetic acid to ketene, followed by addition of acetic acid (Weisselmel, Arpe, industrille organische Chemie,3^rdedition, VCH,1988, pages 193-. Propionic anhydride can be obtained from propionic acid by dehydration or reaction with propionyl chloride. Wherein R is⁵Mixed anhydrides which are not methyl or ethyl can be obtained from acetic acid or propionic acid by acetyl or propionyl chloride followed by reaction with the corresponding carboxylic acid (Ullmanns)dertechnischen Chemie,4^thedition,1983,Verlag Chemie GmbH,Volume 19,page 457)。

Alternatively, the acetic acid or propionic acid formed in the vinylation reaction can be converted to ethanol or propanol by direct hydrogenation in the gas or liquid phase or by hydrogenolysis of the methyl ester intermediate in the presence of a metal catalyst, e.g., in the presence of a supported or unsupported palladium-or platinum-containing hydrogenation catalyst, in which case the liberated methanol can be reused for the esterification of acetic acid or propionic acid (weisselmel, Arpe, industrille or ganische Chemie, 3)^rdedition,VCH,1988,page 191)。

It is likewise possible to convert the acetic acid or propionic acid obtained in the vinylation reaction into the formula R by halogenation reactions known per se in the liquid phase⁶Derivatives of-C (O) -OH, wherein R⁶Is R partially or fully substituted by halogen¹And (4) a base. Among these derivatives, in particular those in which R is used for the preparation of carboxymethylcellulose⁶Is a ClCH₂Monochloroacetic acid of (a) and wherein R⁶Is CH₃The 2-chloropropionic acid of CClH is of great economic importance (Weisselmel, Arpe, Industrial university Organische Chemie, 3)^rdedition,VCH,1988,page 191；Ullmannsder technischen Chemie,4^thedition,1983,Verlag Chemie GmbH,Volume 19,page 458)。

The preferred process of the present invention is explained in detail hereinafter with reference to the flow diagram of FIG. 1 in the context of the starting carboxylic acid which is least volatile and which is obtained as a less volatile residue in the work-up of the reaction mixture. The process of the present invention is not, however, limited to the embodiments shown in the figures and can also be successfully used in those embodiments where any of the reactants are obtained as the less volatile component.

The vinylating reagent vinyl acetate or vinyl propionate is introduced via line (1) and the starting carboxylic acid R-C (O) OH to be vinylated is introduced via line (2) into a mixing vessel (3), and the mixture is introduced from the mixing vessel (3) via line (4) into a reaction vessel (5). The liquid reaction output is introduced via line (6) into a depressurization vessel (7) which is depressurized to standard pressure. Optionally, the liquid reaction output is first passed through a cooling device (7') (shown in dotted lines) and introduced in cooled form via line (6) into the depressurization vessel (7) to keep all components liquid during depressurization. The gas phase which may have formed here is removed via line (8) and the liquid phase which has formed is introduced into a separating vessel (10) via line (9). In a separating vessel (10), the mixture is separated into a mixture rich in vinyl acetate or propionate, acetic acid or propionate and the desired vinyl ester R-C (O) O-CH₂Via line (11) with possible volatile components from the depressurization stage introduced via line (8) and via line (12) into a separation vessel (13). The vinyl acetate or vinyl propionate removed in the separation vessel (13) is recycled via line (14) and combined with the vinyl acetate or vinyl propionate introduced via line (1). Acetic acid or propionic acid formed in the trans-vinylation reaction and obtained in a separating vessel (13), and the desired vinyl ester R-C (O) O-CH ═ CH₂Removed via line (15) and introduced into a separation vessel (16), acetic acid or propionic acid being withdrawn from the separation vessel (16) via line (17), and the desired vinyl ester R-C (O) O-CH ═ CH₂Flows out through a line (18). The vinyl ester obtained via line (18) can be subjected to further fine purification (not shown in FIG. 1). Further purification is taken off via line (17)And the separated acetic acid or propionic acid is used in the above-described derivatization reaction (not shown in fig. 1).

In a preferred embodiment, the less volatile fraction obtained in the separation vessel (10) comprises unconverted starting carboxylic acid R-C (O) OH and the vinylation catalyst, which is removed via line (19) and, optionally after withdrawal of a side stream containing high boilers, is recycled via line (20) (as indicated by the dashed line) as the catalyst recycle stream via line (21). Optionally, fresh catalyst or fresh ligand, optionally in pre-formed form, is added to the catalyst recycle stream via line (22) (shown in phantom) and the mixture of used and fresh catalyst is added to the mixing vessel (3) via line (23). Inhibitors may be added at appropriate points in the reaction section as well as in the processing section to prevent side reactions (not shown in FIG. 1). Suitable separation vessels (10), (13) and (16) are apparatuses which are customarily used for separation operations, such as thin-film evaporators, short-path evaporators or distillation columns. The temperature and pressure conditions to be determined are dictated by the components present in the reaction mixture for processing and can be determined by routine testing. The design of the separation vessel, such as the necessity and number of separation plates, can likewise be determined by routine testing or simulation.

The invention is illustrated in detail in the following examples, but is not limited to the described embodiments.

Examples

For the implementation of the following examples, the experimental setup of fig. 1 was used. In the storage vessel (3), the vinyl acetate (examples 1 to 7 and 15 to 22) or vinyl propionate (examples 8 to 14) via line (1), the starting carboxylic acid R-C (O) OH to be vinylated via line (2) and the catalyst solution via line (23) are mixed and pumped via line (4) into a reaction vessel (5) configured as a flow tube. The liquid reaction mixture withdrawn via line (6) is depressurized to standard pressure in a depressurization vessel (7). The gaseous components formed comprise vinyl acetate or propionate and acetic acid or propionic acid formed, which are removed via line (8). The liquid output removed via line (9) is analyzed by gas chromatography.

The starting carboxylic acid R-C (O) OH used for the conversion to ethylene, the reaction conditions set in the reaction vessel (5), and the desired vinyl ester R-C (O) O-CH ═ CH as determined by gas chromatography₂The space-time yields of (A) are shown in tables 1 to 7 below. By reacting palladium acetate Pd (OAc) in a mixture of vinyl acetate or vinyl propionate and the respective starting carboxylic acid₂The catalyst precursor was mixed with the bidentate nitrogen ligand 1, 10-phenanthroline (examples 1-16 and 21-24) or 2,2' -bipyridine (examples 17-18) to prepare a catalyst solution. In examples 19 to 20, [ Ru (CO) ]₂OAc]_nThe complex serves as a catalyst precursor. In examples 21-23, vinyl acetate was used in molar deficiency based on the molar carboxylic acid input. An active catalyst is formed in the reaction vessel under reaction conditions. The molar ratio of the catalyst precursor is based on the molar amount of palladium or the molar amount of ruthenium. The isononanoic acid used is obtained from the hydroformylation of diisobutylene and the subsequent oxidation of the corresponding aldehyde and contains predominantly 3,5, 5-trimethylhexanoic acid.

TABLE 1 conditions and results for the continuous preparation of vinyl esters using vinyl acetate as the trans-vinylating reagent at elevated pressure in flow tubes (Pd (OAc)₂1, 10-phenanthroline)

TABLE 2 conditions and results for the continuous preparation of vinyl esters using vinyl propionate as the vinylating reagent at elevated pressure in flow tubes (Pd (OAc)₂1, 10-phenanthroline)

TABLE 3 conditions and results for the continuous preparation of vinyl esters at standard pressure using vinyl acetate as the conversion agent in the flow tubes (Pd (OAc)₂1, 10-phenanthroline)

TABLE 4 conditions and results for the continuous preparation of vinyl esters using vinyl acetate as the trans-vinylating reagent at elevated pressure in the flow tubes (Pd (OAc)₂2,2' -bipyridine)

TABLE 5 conditions and results for the continuous production of vinyl esters using vinyl acetate as a trans-vinylating agent at elevated pressure in flow tubes ([ Ru (CO))₂OAc]_n)

TABLE 6 conditions and results for the continuous preparation of vinyl esters using vinyl acetate as the trans-vinylating reagent and an excess of starting carboxylic acid in flow tubes at elevated pressure (Pd (OAc)₂1, 10-phenanthroline)

^[a]Based on the input of the carboxylic acid R-C (O) -OH

TABLE 7 conditions and results for the continuous preparation of vinyl esters in flow tubes at elevated pressure with vinyl acetate as vinylating reagent and with a residence time of less than 1h (Pd (OAc)₂1, 10-phenanthroline)

^[a]Based on the input of the carboxylic acid R-C (O) -OH

As shown by the results in tables 1,2, 4 and 5, in a steady state continuously operated trans-vinylation reaction, very high space-time yields are achieved, which are not achieved in the known reactive distillation processes for the continuous removal of vinyl acetate and acetic acid from the reaction. Furthermore, the known processes require a high input of vinyl acetate, since in reactive distillation large amounts of vinyl acetate have to be used and large reaction volumes are covered.

As the results listed in Table 3 show, high space-time yields can likewise be achieved in the case of the reaction scheme under standard pressure. In the case of the reaction scheme in which vinyl acetate is used in molar deficiency, a high space-time yield of the desired vinyl ester can also be obtained (Table 6). According to Table 7, the residence time in the flow tube can be adjusted to less than 1 hour, so that high-load operating conditions can be established which significantly increase the space-time yield.

The crude product obtained in the depressurization vessel (7) is introduced via line (9) into a thin-film evaporator (10), from which a product comprising vinyl acetate or propionate, acetic acid or propionate and the individual vinyl esters R-C (O) O-CH ═ CH is removed at a shell temperature of 95 ℃ and under reduced pressure₂The top product of (1). The product stream is combined with the gaseous components from the depressurization vessel (7) and conducted via line (12) to a distillation column (13) in which the product mixture is separated into a top fraction consisting of vinyl acetate or vinyl propionate and R-C (O) O-CH-and individual vinyl esters consisting of acetic acid or propionic acid and vinyl esters₂The bottom product of the composition. The vinyl acetate or vinyl propionate-containing product stream is recycled via line (14), the bottom product is introduced via line (15) into a further distillation column (16), from which acetic acid or propionic acid is removed as top product and, after further purification, is used for derivatization reactions, for example for the preparation of n-propyl acetate, n-butyl acetate or isobutyl acetate. The bottom product obtained via scheme (18) is the respective vinyl ester R-C (O) O-CH ═ CH₂. The respective distillation conditions in the thin-film evaporator (10) and in the distillation columns (13) and (16) can be established by routine optimization.

About 5 to 10 parts by mass, based on 100 parts by mass, of the high boiler-containing side stream are discharged from the liquid output of the thin-film evaporator (10) via line (20), while the remainder is recirculated as catalyst recycle stream. Fresh catalyst is added via line (22) in the proportions established in the flow tube (5). By reacting palladium acetate with 1, 10-phenanthroline or 2,2' -bipyridine or [ Ru (CO ]₂OAc]_nTo a mixture of vinyl acetate or vinyl propionate and the respective starting carboxylic acid, the new catalyst is added to the solution.

Claims (29)

1. Of the formula R-C (O) O-CH ═ CH₂By co-production of a carboxylic acid of the formula R-C (O) OH and a carboxylic acid of the formula R¹-C(O)O-CH＝CH₂By a trans-vinylation reaction of the trans-vinylation reagent of (a):

R-C(O)OH+R¹-C(O)O-CH＝CH₂→R¹-C(O)OH+R-C(O)O-CH＝CH₂

wherein R is an aliphatic, cycloaliphatic or aromatic radical having from 2 to 20 carbon atoms, R¹Is methyl or ethyl and coproduced to the carboxylic acid R derived from the formation¹of-C (O) -OHA derivative characterized by:

(a) the transvinylation reaction is continuously carried out at a temperature of 90-160 ℃ and a pressure of 0.8-2MPa in the presence of a transition metal catalyst containing at least one transition metal selected from ruthenium, osmium, rhodium, iridium, palladium and platinum without taking out the reactants;

(b) separating the resulting reaction mixture into its components and removing the compound of formula R-C (O) O-CH ═ CH₂Vinyl esters of the formula R¹-C (O) -OH; and

(c) converting said carboxylic acid obtained after step b to formula R¹-C(O)-X、R¹-CH₂-OH or R⁶Derivatives of-c (O) -OH, wherein X is ethyleneoxy O-CH ═ CH₂Halogen of the formula OR²Alkoxy of (2), wherein R²Is an unsubstituted hydrocarbon radical having from 1 to 10 carbon atoms, of the formula NR³R⁴Wherein R is³And R⁴Each independently hydrogen or unsubstituted hydrocarbyl having 1 to 10 carbon atoms, or of the formula O-C (O) -R⁵Wherein R is⁵Is hydrogen or an unsubstituted hydrocarbon radical having 1 to 10 carbon atoms, and R⁶Is R partially or fully substituted by halogen¹And (4) a base.

2. The method of claim 1, wherein the reaction is carried out at a temperature of 90-150 ℃.

3. The method of claim 2, wherein the reaction is carried out at a temperature of 90-140 ℃.

4. The process according to claim 1, wherein the reaction is carried out at a pressure of 0.8 to 2MPa and a temperature of 90 to 140 ℃.

5. The method of claim 1, wherein the carboxylic acid of formula R-C (o) OH is selected from the group consisting of propionic acid, n-butyric acid, isobutyric acid, n-valeric acid, 2-methylbutyric acid, 3-methylbutyric acid, pivalic acid, n-heptanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, n-octanoic acid, n-nonanoic acid, isononanoic acid, neononanoic acid, 3,5, 5-trimethylhexanoic acid, n-decanoic acid, 2-propylheptanoic acid, neodecanoic acid, mixtures of isomeric C9 to C11 acids, mixtures of isomeric C15 to C19 acids, dodecanoic acid, tridecanoic acid, palmitic acid, stearic acid, benzoic acid, naphthalene carboxylic acid, acrylic acid, butenoic acid, and methacrylic acid.

6. The process of claim 1 or 2, wherein the transition metal catalyst contains a monodentate or multidentate organonitrogen or organophosphine ligand in complexed form.

7. The process of claim 4, wherein the transition metal catalyst comprises a monodentate or multidentate organonitrogen or organophosphine ligand in complexed form.

8. The process according to claim 1 or 2, characterized in that the total concentration of transition metals is from 0.005 to 1.5 mol%, based on the starting carboxylic acid used in a deficit.

9. The process according to claim 8, wherein the total concentration of transition metals is from 0.01 to 1.0 mol%, based on the starting carboxylic acids used in the deficit.

10. The process of claim 1 or 2, wherein the molar ratio of transition metal to monodentate or multidentate organic nitrogen or organic phosphine ligand is from 1:1 to 1: 40.

11. The method of claim 10, wherein the molar ratio of transition metal to monodentate or multidentate organic nitrogen or organophosphine ligand is from 1:3 to 1: 30.

12. A process according to claim 1 or 2, wherein the transition metal used is palladium and the multidentate organic nitrogen ligand used is 1, 10-phenanthroline or 2,2' -bipyridine.

13. A process according to claim 4, wherein the transition metal used is palladium and the multidentate organic nitrogen ligand used is 1, 10-phenanthroline or 2,2' -bipyridine.

14. The process according to claim 1 or 2, wherein the transition metal catalyst additionally contains a redox-active transition metal of group Ib of the periodic table of the elements and an alkali metal compound.

15. The process according to claim 14, characterized in that in addition to the transition metal, copper from group I of the periodic table of the elements is additionally used as redox-active transition metal and a lithium compound selected from the group consisting of lithium carboxylates, lithium carbonates, lithium hydrogen carbonates, lithium chlorides and lithium hydroxides is used as alkali metal compound.

16. The process according to claim 15, wherein the transition metal used is palladium.

17. The process according to claim 1 or 2, wherein the reaction is carried out in a tubular reactor.

18. The method of claim 4, wherein the reaction is carried out in a tubular reactor.

19. The method of claim 18, wherein the tubular reactor is provided with a circulation pump and optionally a heat exchanger.

20. The method of claim 1 OR 2, wherein X is of the formula OR²In the case of alkoxy groups of (1)，R²Is methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl.

21. The process of claim 20, wherein the acetic acid is converted to methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, or isobutyl acetate.

22. The process of claim 20, wherein said propionic acid is converted to methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, n-butyl propionate, or isobutyl propionate.

23. The method of claim 1 or 2, wherein X is an amino group NR³R⁴In the case of (A), R³And R⁴Each independently hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl.

24. The method of claim 1 or 2, wherein X is carboxy, O-C, (O) -R⁵In the case of (A), R⁵Is methyl or ethyl.

25. The process of claim 24, wherein the acetic acid is converted to acetic anhydride.

26. The method of claim 24, wherein the propionic acid is converted to propionic anhydride.

27. The method of claim 1 or 2, wherein at R⁶In the case of-C (O) -OH, R⁶Is a ClCH₂-or CH₃-CClH-。

28. The method according to claim 1 or 2,characterized in that in R¹In the case of methyl, the acetic acid formed is converted into ethanol.

29. The method of claim 1 or 2, wherein at R¹In the case of ethyl, the propionic acid formed is converted into propanol.