JPH0433784B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing organic quaternary ammonium salts.

Organic quaternary ammonium salts are compounds that are extremely useful as phase transfer catalysts for various reactions, and are generally produced using the general formula [] [In the formula, R ₁ , R ₂ and R ₃ are the same or different and each represents an alkyl group or an aralkyl group. ] A tertiary amine represented by the general formula [] R ₄ -X [] [In the formula, R ₄ represents an alkyl group or an aralkyl group, and X represents a halogen atom. ] A method of reacting with a halide shown in is known.

However, in this production method, when the amount of tertiary amine and halide used is around the same molar amount, the reaction is slow and the halide decomposes, making it difficult to obtain the desired product in high yield. It was necessary to use a considerable excess of one or the other to accelerate the reaction.

However, in this case, when using the resulting reaction product as a catalyst, in order to avoid adverse effects such as side reactions in the reaction, it is necessary to remove excess tertiary amine or halide from the resulting reaction product and regenerate the target product. An extraction operation using crystals or the like is required, which poses problems as an industrial production method, such as a decrease in the yield of the desired quaternary ammonium salt, a rise in production costs, and the handling of highly toxic powders.

The present inventors have made extensive studies on the method for producing quaternary ammonium salts in order to improve the above-mentioned drawbacks. The inventors have discovered that the desired product can be obtained in high yield and with high purity by using benzyl nitriles as a reaction solvent in the reaction, leading to the completion of the present invention.

That is, the present invention is based on the general formula [] [In the formula, R ₁ , R ₂ and R ₃ are the same or different and each represents an alkyl group or an aralkyl group. ] A tertiary amine represented by the general formula [] R ₄ -X [] [In the formula, R ₄ represents an alkyl group or an aralkyl group, and X represents a halogen atom. ] By reacting with a halide represented by the general formula [] [In the formula, R ₁ , R ₂ , R ₃ , R ₄ and X have the same meanings as above. ] The present invention provides a method for producing an organic quaternary ammonium salt characterized by using benzyl nitriles as a reaction solvent in producing the organic quaternary ammonium salt shown in the following.

The method of the present invention will be explained in detail below.

Benzyl nitriles used as solvents in the present invention include, for example, benzyl nitrile, o-, m- or p-chlorobenzyl nitrile, o-, m- or p-bromobenzyl nitrile, o-, m- or p- Fluorobenzyl nitrile, o-, m- or p-methoxybenzyl nitrile, o-, m- or p-(difluoromethoxy)benzyl nitrile, o-, m- or p-
Ethoxybenzylnitrile, o-, m- or p
- phenoxybenzyl nitrile, o-, m- or p-methylbenzyl nitrile, o-, m- or p-ethylbenzyl nitrile, o-, m- or p-n-propylbenzyl nitrile, o-, m-
- or p-isopropylbenzylnitrile, o
-, m- or p-n-butylbenzyl nitrile, o-, m- or p-isobutylbenzyl nitrile, o-, m- or p-trichloromethylbenzyl nitrile, 3,4-dimethoxybenzyl nitrile, 3,4- dimethylbenzylnitrile,
3,4-methyleneoxybenzylnitrile, 3,
Examples include 4-dibromobenzylnitrile, 3,4-dichlorobenzylnitrile, 2,4-dibromobenzylnitrile, 2,4-dichlorobenzylnitrile, etc. The amount used is not particularly limited, but in practice, It is preferably 1 to 10 parts based on 1 part of the raw material alkyl halide.

Examples of the halide represented by the general formula [] include methyl chloride, bromide or iodide, ethyl chloride, bromide or iodide, n-propyl chloride, bromide or iodide, isopropyl chloride, bromide or iodide, n-butyl chloride, bromide or iodide,
Examples include secondary butyl chloride, bromide or iodide, benzyl chloride, bromide or iodide.

Examples of the tertiary amine represented by the general formula [] include trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, dimethylbenzylamine, diethylbenzylamine, di-n-propylbenzylamine, and methylethylbenzylamine. , methyl n-propylbenzylamine, ethyl n-propylbenzylamine, ethyldibenzylamine, o-, m- or chlorobenzylethylamine, p-methoxybenzylethylamine, o-, m- or p-phenoxybenzylethylamine, Examples include benzyl lauryl methylamine, benzyl methyl stearyl amine, benzyl methyl octyl amine, dimethyl lauryl amine, dimethyl stearyl amine, dimethyl octadecyl amine, dimethyl hexadecyl amine, methyl distearyl amine, tricapryl amine, etc., and the amount used is Practically,
The amount is preferably 1.0 molar equivalent to 1.2 molar equivalent relative to the halide.

The reaction temperature is arbitrary between room temperature and 200°C, but the reaction is slow near room temperature, and at high temperatures the raw material halide is likely to decompose, resulting in the formation of by-product hydrogen halide and the other raw material tertiary. Preferably 70 to 150, since side reactions such as amine forming salts occur.
Perform within the range of °C.

The organic quaternary ammonium salt obtained by the method of the present invention is of high purity and can be used as a phase transfer catalyst in the alkylation reaction of benzyl nitriles with alkyl halides in a heterogeneous system, which is one of its major uses. In some cases, the organic quaternary ammonium can be subjected to the alkylation reaction as a solution of the benzyl nitriles without being taken out, which is extremely advantageous especially during production on an industrial scale.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is of course not limited to the following Examples.

Example 1 In a 500 ml four-necked flask, 151.6 g of p-chlorobenzyl nitrile and 68.5 g of n-butyl bromide
(0.50 mol), tri-n-butylamine 101.9 g (0.55
mol), then heated and gradually raised the temperature until the internal temperature reached 105℃, then continued stirring at the same temperature, and heated it until the internal temperature reached 105℃.
After a period of time, it was confirmed by gas chromatography that unreacted n-butyl bromide had disappeared, and the mixture was cooled to 50° C. or lower to obtain 322 g of a reaction solution.

The reaction solution was analyzed by silver nitrate titration, neutralization titration with a caustic soda solution, and the picrate method (measurement of the reaction product with picric acid by absorbance). As a result, the content of tetra-n-butylammonium bromide was 47.6%. The yield in terms of purity based on n-butyl bromide was 95.1%.

In addition, p-chlorobenzyl nitrile content is 47.0%
The recovery rate for the amount used was 99.8%.

Reference Example 1 The reaction solution obtained in Example 1 above, that is, 19.0 g of a p-chlorobenzyl nitrile solution of tetra-n-butylammonium bromide (0.028 mol of tetra-n-butylammonium bromide and p-
containing 0.059 mol of chlorobenzylnitrile);
136.0 g (1.63 mol) of 48% concentration sodium hydroxide
and into a 500 ml four-necked flask and heat to 42
The temperature was raised to ℃. In this, a mixture of 51.7 g (0.34 mol) of p-chlorobenzyl nitrile and 110.0 g (1.40 mol) of isopropyl chloride was added at an internal temperature of 42 to 43 mol.
The dropwise addition took 3 hours at ℃.

After the dropwise addition, stirring was continued under reflux at the same temperature, and after 3 hours and 10 minutes, it was confirmed by gas chromatography that unreacted p-chlorobenzyl nitrile had disappeared. After cooling to 20°C, 100 g of water was added and the organic layer was separated. The mixture was separated into an aqueous layer. The organic layer was further washed with 100 g of water and concentrated under normal pressure to remove excess isopropyl chloride.

The yield of the concentrate was 77.1g, which was the desired amount of 3-methyl-2.
The purity of -(4-chlorophenyl)butyronitrile as determined by gas chromatography was 95.5%, and the yield in terms of purity relative to p-chlorobenzylnitrile was 97.0%.

Example 2 In a 500 ml four-necked flask, 227.4 g of p-chlorobenzyl nitrile and 46.3 g of n-butyl chloride (0.50 g
101.9 g (0.55 mol) of tri-n-butylamine was added, and the temperature was gradually raised until the internal temperature reached 100 mol).
After reaching ℃, stirring was continued at the same temperature for 35 hours, and after confirming that unreacted n-butyl chloride had disappeared by gas chromatography, the reaction solution was cooled to below 50℃.
Got 375g.

As a result of analysis of the reaction solution, the content of tetra-n-butylammonium chloride was 35.1%, and the yield in terms of purity based on n-butyl chloride was 94.7%.

In addition, p-chlorobenzyl nitrile content is 60.6%
The recovery rate for the amount used was 99.9%.

Reference Example 2 The reaction solution obtained in Example 2 above, that is, 11.1 g of a solution of tetra-n-butylammonium chloride in p-chlorobenzyl nitrile (0.014 mol of tetra-n-butylammonium chloride and p-
containing 0.044 mol of chlorobenzylnitrile) and 48
% sodium hydroxide (1.63 mol) was placed in a 500 ml four-necked flask and heated to 42°C.

In this, 53.9g of p-chlorobenzylnitrile
(0.36 mol) and isopropyl chloride 110.0g
(1.40 mol) was added dropwise over a period of 3 hours at an internal temperature of 42 to 43°C.

After the dropwise addition, stirring was further continued under reflux at the same temperature, and after 2 hours and 40 minutes, unreacted p-chlorobenzyl nitrile disappeared by gas chromatography analysis.

Hereinafter, the same procedure as in Example 1 was carried out to obtain 76.2 g of concentrate.
I got it. The purity of the target 3-methyl-2-(4-chlorophenyl)butyronitrile as determined by gas chromatography was 94.7%, and the yield in terms of purity based on the p-chlorobenzylnitrile used was 95.0%.

Claims (1)

[Claims] 1. General formula [In the formula, R ₁ , R ₂ and R ₃ are each the same or different and represent an alkyl group or an aralkyl group. ] A tertiary amine represented by the general formula R ₄ -X [wherein R ₄ represents an alkyl group or an aralkyl group, and X represents a halogen atom. ] By reacting with a halide represented by the general formula [In the formula, R ₁ , R ₂ , R ₃ , R ₄ and X have the same meanings as above. ] A method for producing an organic quaternary ammonium salt, which comprises using benzyl nitriles as a reaction solvent when producing the organic quaternary ammonium salt represented by the formula. 2. The method according to claim 1, in which p-halogenobenzylnitrile is used as the benzylnitrile.