JPS6213340B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing alkylidene dialkanoates by hydrogenating anhydrides of monobasic aliphatic carboxylic acids in the presence of a catalyst.

As a method for producing dicarboxylates by hydrogenation of carboxylic acid anhydrides, a method is known in which a complex of a group noble metal of the periodic table and an amphiphilic ligand such as phosphine, arsine or stibine is used as a catalyst. (USP3579566). However, the above method has a low selectivity for dicarboxylate and cannot be said to be an industrially suitable method.

Furthermore, a method for hydrogenating carboxylic acid anhydride using cobalt octacarbonyl as a catalyst to produce carboxylic acid and aldehyde is disclosed in Japanese Patent Publication No. 1985-19285, and in Example 1, acetic anhydride is hydrogenated to produce acetic acid and It has been described that ethylidene acetate is produced in the reaction to obtain acetaldehyde, but this reaction is originally intended to obtain a carboxylic acid and an aldehyde, or an aldehyde carboxylic acid, so it is difficult to obtain an alkylidene dialkanoate. As for the reaction, the production of aldehyde or carboxylic acid is rather a side reaction.

The present inventors have conducted various studies on a method for obtaining alkylidene dialkanoate with good selectivity by hydrogenating anhydrides of monobasic aliphatic carboxylic acids. We have discovered that alkylidene dialkanoate can be obtained with good selectivity by carrying out the above reaction in the presence of a catalyst consisting of an amide compound,
This has led to the present invention.

The present invention will be explained in detail below.

Specific examples of monobasic aliphatic carboxylic acid anhydrides used as raw materials in the method of the present invention include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, stearic anhydride, acetic anhydride propionic anhydride, etc. Particularly preferred is acetic anhydride.

As hydrogen, another raw material in the method of the present invention, it is possible to use pure hydrogen gas, but in order to keep the catalyst stable in the reaction system, synthesis gas, which is a mixture of carbon monoxide and hydrogen, is used. It is preferable to use The molar ratio of hydrogen to carbon monoxide ( _H2 /CO) of the synthesis gas is usually 0.05-20, preferably 0.1-10. Furthermore, if desired, a gas inert to the reaction, such as nitrogen, helium, argon, methane, ethane, etc., can be supplied into the reaction system together with hydrogen gas or synthesis gas.

The first component of the catalyst in the process of the invention is a platinum group metal, with rhodium or palladium being preferred. These metals are used alone or as a compound. Examples of compounds include halides such as ruthenium trichloride (), rhodium trichloride (), palladium dichloride (), osmium trichloride (), iridium trichloride (), platinum dichloride (), and rhodium trihydroxide. hydroxides such as (),
Acetate salts such as palladium acetate (), carbonyl complexes such as hexalodium (O) hexadecacarbonyl, bromorodium () dicarbonyl, dipalladium (O) tolucarbonyl, tris(acetylacetonato)rhodium (), bis(acetyl In addition to chelate compounds such as acetonato) palladium (), compounds such as chloroplatinic () acid may be mentioned. The amount of these platinum group metals to be used is 0.000001 to 0.1 gram atom, preferably 0.0001 to 0.05 gram atom, based on 1 mol of monobasic aliphatic carboxylic acid anhydride.

The second component of the catalyst is a halogen compound. Specifically, hydrogen halides such as hydrogen chloride, hydrogen bromide, and hydrogen iodide, alkyl halides such as methyl bromide and methyl iodide, or simple substances such as iodine are used. The amount of these halogen compounds used is usually 0.1 to 10,000 per gram atom of platinum group metal.
mol, preferably 5 to 500 mol.

The third component of the catalyst is a tertiary amine or amide compound. Examples of amine compounds include pyridine, picoline, lutidine, pyrimidine, pyrazine, quinoline, 1,10-phenanthroline, 2,
Heteroaromatic tertiary amines such as 2'-bipyridyl, aliphatic or alicyclic amines such as triethylamine, tri-n-butylamine, benzyldimethylamine, N,N,N',N'-tetraethylethylenediamine, tricyclohexylamine, etc. Tertiary amine, N-
Ethylpyrrolidine, N-methylpiperidine, N,
Examples include N-substituted cyclic tertiary amines such as N'-dimethylpiperazine. Examples of amide compounds include N-substituted lactams such as N-methylpyrrolidone and N-ethylpiperidone, N,N-disubstituted fatty acid amides such as N,N-dimethylacetamide,
Examples include tertiary phosphotriamides such as hexamethylphosphotriamide. The amount of these tertiary amines or amide compounds to be used is not particularly limited, but is usually about 0.1 to 10,000 mol, preferably about 1 to 500 mol, per gram atom of platinum group metal.

The reaction of the present invention is usually carried out in the presence of excess hydrogen gas, at a reaction pressure of 1 to 350 atm, preferably 20 to 250 atm, and at a reaction temperature of 20 to 350°C, preferably 100 to 250°C. The reaction is carried out by keeping the carboxylic acid anhydride, which is the raw material for the reaction, in a liquid phase. In this case, the reaction can be carried out without using a solvent, but usually
Aromatic hydrocarbons such as benzene, aliphatic hydrocarbons such as octane, ethers such as tetrahydrofuran and dioxane, carboxylic acids such as acetic acid, carboxylic acid esters such as methyl acetate, ketones such as acetone, acetonitrile, benzonitrile, etc. The reaction is carried out using a solvent such as a nitrile or an alcohol such as t-butyl alcohol, or using an excess of a tertiary amine or amide compound as a catalyst component which also serves as a solvent.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 532 mmole of acetic anhydride, 1.25 mmole of rhodium trichloride trihydrate, 42 mmole of methyl iodide and α- 12.5 mmole of picoline was charged, and the reaction was carried out for 5 hours at a hydrogen gas partial pressure of 62.5 Kg/cm ² , a carbon monoxide partial pressure of 12.5 Kg/cm ² , and a reaction temperature of 150°C. Analysis of the reaction product liquid by gas chromatography revealed that the conversion rate of acetic anhydride was 68%, and it was confirmed that 144 mmole of ethylidene diacetate and 203 mmole of acetic acid were produced.

Example 2 Propionic anhydride instead of acetic anhydride
The reaction was carried out in the same manner as in Example 1 except that 328 mmole was used. As a result, the conversion rate of propionic anhydride was 28%, and the production amounts of propionic acid and propionic acid were respectively
They were 25 mmole and 153 mmole.

Example 3 Hydrogen partial pressure and carbon monoxide partial pressure are both 37.5
The reaction was carried out in the same manner as in Example 1 except that the amount was changed to Kg/cm ² . As a result, the conversion rate of acetic anhydride was 46
%, and the production amounts of ethylidene diacetate and acetic acid are 73 mmole and acetic acid 150 mmole, respectively.
It was hot.

Example 4 The reaction was carried out in the same manner as in Example 1 except that the reaction temperature was changed to 170°C. As a result, the conversion rate of acetic anhydride was 97%, and ethylidene diacetate, acetic acid and acetaldehyde were respectively
It produced 151mmole, 243mmole and 1mmole.

Example 5 The reaction was carried out in the same manner as in Example 1, except that the amount of acetic anhydride used was changed to 266 mmole, and 30 ml of ethyl acetate was used as the solvent. As a result, the conversion rate of acetic anhydride was 99%, and the amounts of ethylidene diacetate, acetic acid, and acetaldehyde produced were 64 mmole, 197 mmole, and 42 mmole, respectively.

Example 6 N-methylpyrrolidone instead of α-picoline
The reaction was carried out in the same manner as in Example 1 except that 25 mmole was used. As a result, the conversion rate of acetic anhydride is
99%, and the production amounts of ethylidene diacetate, acetic acid and acetaldehyde are respectively
They were 172 mmole, 260 mmole and 5 mmole.

Example 7 2 mmole of palladium acetate was used instead of rhodium trichloride trihydrate, and the amount of methyl iodide used was
The reaction was carried out in the same manner as in Example 1, except that the hydrogen partial pressure and carbon monoxide partial pressure were changed to 50 Kg/cm ² and 0 Kg/cm ² , respectively. As a result, the conversion rate of acetic anhydride was 99%, and the production amounts of ethylidene diacetate, acetic acid and acetaldehyde were 169 mmole, 307 mmole and 307 mmole, respectively.
It was 49 mmole.

Comparative Example The reaction was carried out in the same manner as in Example 1 except that α-picoline was not used. As a result, the conversion rate of acetic anhydride was 16%, and the production amounts of ethylidene diacetate and acetic acid were 18 mmole and 99 mmole.
It was hot.

Claims (1)

[Claims] 1. A method for producing an alkylidene dialkanoate, which comprises reacting an anhydride of a monobasic aliphatic carboxylic acid with hydrogen in the presence of a catalyst consisting of a platinum group metal, a halogen compound, and a tertiary amine or amide compound. .