JPS5998054A - Preparation of 3-mercaptopropionitrile or its 2-methyl substituted compound - Google Patents

Abstract

PURPOSE:To prepare the titled compound useful as a raw material of pharmaceuticals, agricultural chemicals, synthetic resins, perfumes, etc., in high yield, at a low cost, by reacting a 2,3-unsaturated propionitrile with an alkali sulfide or alkali hydrosulfide in the presence of carbon disulfide, and treating the reaction product with an acid. CONSTITUTION:The objective compound of formula III is prepared by reacting the 2,3-unsaturated propionitrile of formula I (R is H or methyl) with an alkali sulfide or alkali hydrosulfide in the presence of carbon disulfide at 0-45 deg.C, and acidifying the resultant thioxanthogenic acid of formula II with hydrochloric acid, sulfuric acid, etc. The reaction is carried out preferably using 1-2mol of the alkali sulfide or alkali hydrosulfide and 1-3mol of carbon disulfide based on 1mol of the compound of formula I , keeping the amount of carbon disulfide in the reaction system always excess to the nitrile.

Description

Detailed Description of the Invention The present invention relates to the production of 3-mercaptopropionitrile or its 2-methyl substituted product, which is a compound useful as a raw material for many organic synthetic products including medicines, agricultural chemicals, synthetic resins, and fragrances. It is about law.

Various methods have been known for producing 3-mercaptopropionitrile. Examples include direct reaction of acrylonitrile with hydrogen sulfide in 3-2.
There are ways to obtain mercaptopropionitrile.

(t) CH2= CHCN +H,8-+H8CH2
CH2CN catalyst: sulfur/organic amine yield 62-67%
(US Patent No. 3280163) (2) CH2
= CHCN +H28+H8CH2CH2CN catalyst:
Sulfur/organic amine, solvent: benzene yield 92 cm (Japanese Patent Publication No. 18369/1983) (a) CH27CHCN10H,8-+H8CH,CH2
CN catalyst: sulfur/triethylamine yield 74% (Specification of Japanese Patent Publication No. 49-46290) In this reaction, a large excess of hydrogen sulfide was used to avoid the formation of the by-product 3.3°-teodipropioniole). (3 to 10 times the mole) under pressure. In order to improve economic efficiency, excess hydrogen sulfide must be recovered and recycled, and the high-pressure equipment becomes larger than necessary, which is very disadvantageous as an industrial production method.

The present inventors have discovered that 2,3-unsaturated propionitrile, which is produced in large quantities as a raw material for synthetic fibers and synthetic resins,
That is, as a result of intensive research to develop an economical industrial production method using acrylonitrile or methacrylonitrile as a raw material and an inexpensive sulfur source, we found that alkali sulfide or alkali hydrosulfide was used as the sulfur source, and during the reaction. By coexisting carbon disulfide to first produce thioxanthates and then acidifying them with acid, 3-mercaptonitrile or its 2-methyl substituted product can be easily obtained in high yield even under normal pressure. We have discovered this and arrived at the present invention. The details will be explained below.

One of the raw materials in the present invention is 2 represented by the following formula (1),
3-unsaturated propionitrile.

0H2-C-CN (t) (In the formula, R is hydrogen or a methyl group) The other raw material is an alkali sulfide represented by the following formula (2).

Alternatively, it is an alkali hydrosulfide represented by the following formula (3), or a mixture of both.

M28 (2) M 8 H (3) (In the formula, M is an alkali metal, alkaline earth metal, or ammonium ion) When these are reacted in the coexistence of carbon disulfide.

Thioxanthates (4) are produced according to the following formula.

When this is further acidified by treatment with an acid such as hydrochloric acid or sulfuric acid, the target product 3-mercaptopropionitrile or its 2-methyl substituted product (5) is obtained and carbon disulfide is regenerated.

(Li (2) (3) M808
To CH2Cl-1□〉 n5ch26ucN+Mcn+cs2 2,3-Unsaturated propionitrile, i.e., acrylonitrile i or methacrylonitrile, as a starting material in the present invention is industrially produced in large quantities as a raw material for synthetic fibers and synthetic resins. What you have is fine.

Alkali sulfides or alkali hydrosulfides are also produced industrially.
Fresh, high-purity products are preferable, such as sodium sulfide and potassium sulfide.

Calcium sulfide, ammonium sulfide or sodium bisulfide, potassium bisulfide, water'□calcium sulfide.

Selected from ammonium hydrosulfide, etc. Among these, sodium sulfide or sodium hydrosulfide is preferred because of its economic efficiency. A mixture of these may also be used without any problem in terms of reaction.

Usually, the alkali sulfide or alkali hydrosulfide is used for the reaction after being dissolved in an alcohol, water alone, or a mixture of alcohol and water. The alcohol is selected from methanol, ethanol, isozolopanol, alcohol, propylene glycol, glycerin, etc.
A species or two or more species can be used.

2.3-As for the convenient molar ratio of unsaturated propionitrile and alkali sulfide or alkali hydrosulfide and carbon disulfide, the stoichiometric amount is the best solution from an economic point of view. In order to suppress the production of propionitrile as much as possible, it is appropriate to use alkali sulfide or alkali hydrosulfide and carbon disulfide in a slightly excessive amount. For 1.0 mole of 2,3-unsaturated propionitrile, alkali sulfide or alkali hydrosulfide is 1.0 to 2.0 mole, and carbon disulfide is 1.0 mole.
About 0 to 3.0 mol is preferable.

The reaction method involves adding 2,3-unsaturated propionitrile and carbon disulfide to a solution of alkali sulfide or alkali hydrosulfide in alcohol, water, or a mixture of alcohol and water. Saturated propionitrile and carbon disulfide can be added simultaneously, in a mixture, or individually. In the case of Isn, it is also desirable to adjust the reaction so that carbon disulfide is always present in excess over nitrile in one reaction system.

There are no particular restrictions on the reaction temperature for producing thioxanthates, but from a safety perspective, temperatures below the boiling point of carbon disulfide are best from 0 to 4.
A temperature of 5°C is desirable. Since the reaction is exothermic, it is appropriately cooled.

The produced thioxanthate solution is a viscous reddish-brown liquid, and when acid is added to make it acidic, 3-mercaptopropionitrile is produced and carbon disulfide is regenerated, and the aqueous and organic layers are separated. Separate into two layers. The temperature at which the acid is added is preferably around room temperature.

It is better to add the acid after diluting it with water so as not to increase the temperature increase due to the heat of neutralization. Carbon disulfide is first recovered by separating the organic layer and the aqueous layer and distilling the organic layer. Then, it is distilled under reduced pressure to obtain 3-mercaptopropionitriles. Alternatively, the liquid separated into two layers may be mixed with a suitable water-insoluble solvent such as benzene, toluene, 1.
2-dichloroethane/dichloromethane/1.1. l
-) It can also be obtained by extraction with dichloroethane, chloroform, diethyl ether, etc. and distillation.

Typical examples using the method of the present invention are shown below.

The present invention will be described in more detail, but the present invention is not limited to these embodiments. In the examples, "parts" means "parts by weight."

Example 1 Sodium sulfide (sulfide) IJ was placed in a 500 ml reaction tank equipped with a stirrer, a thermometer, a dropping tank, and a cooler.
87.6 parts of aluminum (purity 98.0% by weight, remainder water) was dissolved in a mixed solution of 60 parts of methanol and 60 parts of water and kept at 20°C.

While stirring, 91.2 parts of carbon disulfide was quickly added dropwise, and then 53 parts of acrylonitrile (IJ) was slowly added dropwise. In this reaction, the temperature of the reaction solution rose due to exothermic reaction, so when the reaction temperature was maintained at 20° C. by external cooling, the reaction solution became a viscous reddish-brown solution.

After the dropwise addition of acrylonitrile was completed, stirring was continued at 20° C. for about 3 hours, and then 400 parts of 20% by weight hydrochloric acid was added dropwise. When the pH of the aqueous layer of the reaction solution reached 2, the dropping of hydrochloric acid was stopped. The reaction solution has an aqueous layer from the top.

The mixture was separated into three layers: an organic layer and a carbon disulfide layer, and these were separated into two layers: an aqueous layer, an organic layer, and a carbon disulfide layer using a separating funnel.

A drying agent (anhydrous sodium sulfate) is added to the mixture of the organic layer and the carbon disulfide layer, and the mixture is dried. Carbon disulfide is recovered by atmospheric distillation, and then 3-mercaptopropionitrile and the by-products are recovered by vacuum distillation. 3'-y-ocypropionitrile was obtained. The results are summarized in Table-1.

Table 1 Tatami Acrylonitrile Pace Example 2 The same apparatus as in Example 1 was prepared. In a 1-liter reaction tank, 87.6 parts of sodium sulfide (sodium sulfide purity: 98% by weight, the remainder was water) was dissolved in a mixed solution of 60 parts of methanol and 60 parts of water, and the mixture was maintained at 20°C.

While stirring, 91.2 parts of carbon disulfide was quickly added dropwise, and then 6 parts of methacriconitrile were slowly added dropwise. This reaction is exothermic and the temperature of the reaction solution is
When the reaction temperature was maintained at 20° C. by external cooling, the reaction solution gradually became a slurry of orange crystals. After the completion of the dropwise addition of methacrylonitrile, stirring was continued at 20° C. for about 3 hours, and then 400 parts of 20% by weight hydrochloric acid was added dropwise to acidify the mixture. When the pH of the aqueous layer of the reaction solution reached 2, the dropping of hydrochloric acid was stopped. The reaction solution was separated from above into two layers, an aqueous layer and an organic layer, and these were separated into two layers, an aqueous layer and an organic layer, using a separating funnel.

After adding a desiccant (anhydrous mirabilite) to the organic layer and drying it, carbon disulfide was recovered by atmospheric distillation, and then 3-mercapto-2-methylpropionitrile and by-product 3.3 were recovered by vacuum distillation.
ly-obis(2-methylpropionitrile) was obtained. The distillation results are summarized in Table-2K.

Table 2 Example 3 A device similar to Example 1 was prepared. Pour 363 parts of a 5% by weight ammonium sulfide aqueous solution into a 1 liter reaction tank and add 20
It was kept at ℃.

While stirring, 27.4 parts of carbon disulfide was quickly added dropwise, and then 16.8 parts of methacrylonitrile was slowly added dropwise. In this reaction, the temperature of the reaction solution rose due to exothermic reaction, so when the reaction temperature was maintained at 20° C. by external cooling, the reaction solution became a reddish-orange solution. After the completion of the dropwise addition of IJ, stirring was continued at 20° C. for about 3 hours, and 100 parts of hydrochloric acid (wt%) of the two layers was added dropwise to acidify the mixture. When the pH of the aqueous layer of the reaction solution reached 2, the dropping of hydrochloric acid was stopped. The reaction solution was separated into two layers, an aqueous layer and an organic layer, and these were separated into an aqueous layer and an organic layer using a separating funnel. After adding a desiccant (anhydrous mirabilite) to the organic layer and drying it, carbon disulfide was recovered by distillation at atmospheric pressure, and then 3-mercapto-2-methylpropionitrile and the by-product 3,31-thiobis were recovered by distillation under reduced pressure. (2
-methylpropionitrile) was obtained. The results are summarized in Table 3.

Table 3 Example 4 A device similar to Example 1 was prepared. 85.6 parts of sodium bisulfide (sodium bisulfide purity: 72.0 weight: 1 part by weight is water) was dissolved in a mixed solution of 80 parts of methanol and 20 parts of water and charged into a 500 μl reaction tank and kept at 20°C. Ta.

While stirring, 91.2 parts of carbon disulfide was quickly added dropwise, and then 53 parts of acrylonitrile was slowly added dropwise. In this reaction, the temperature of the reaction solution rose due to exothermic reaction, so when the reaction temperature was maintained at 20° C. by external cooling, the reaction solution became a viscous reddish-brown solution.

After the dropwise addition of acrylonitrile was completed, stirring was continued at 20° C. for about 3 hours, and then 300 parts of 15% by weight hydrochloric acid was added dropwise.

13 When the pH of the aqueous layer of the reaction solution reached 2, the dropping of hydrochloric acid was stopped. The reaction solution has an aqueous layer from the top.

It was separated into three layers: an organic layer and a carbon disulfide layer. These were separated into two layers: an aqueous layer, an organic layer, and a carbon disulfide layer using a separating funnel. After adding a desiccant (anhydrous sodium sulfate) to the mixture of organic layer and carbon disulfide layer and drying.

Carbon disulfide is recovered by atmospheric distillation, and then 3- is recovered by vacuum distillation.
Mercaptopropionitrile 3.3I-teodipropionitrile was obtained. The results are summarized in Table 4.

Table 4 Example 5 A device similar to Example 1 was prepared. Put 317 parts of a 25% by weight potassium hydrogen sulfide aqueous solution into a 11J tube reaction tank.
It was kept at 0°C.

Without stirring, 91.2 parts of carbon disulfide was quickly added dropwise, and then 53 parts of acrylonitrile was slowly added dropwise. In this reaction, the temperature of the reaction solution rose due to exothermic reaction, so when the reaction temperature was maintained at 20° C. by external cooling, the reaction solution became a reddish-brown viscous liquid. After the dropwise addition of acrylonitrile was completed, stirring was continued at 20° C. for about 3 hours, and then 300 parts of 15% by weight hydrochloric acid was added dropwise to acidify the mixture. When the pH of the aqueous layer of the reaction solution reached 2, the dropping of hydrochloric acid was stopped. The reaction solution is separated into three layers from the top: an aqueous layer, an organic layer, and a carbon disulfide layer, and these are separated into an aqueous layer and an organic layer using a separation rotor.

The liquid was separated into two layers: a carbon disulfide layer.

A desiccant (anhydrous sodium sulfate) is added to the mixed solution of the organic layer and the carbon disulfide layer, and after drying, carbon disulfide is recovered by atmospheric distillation, and then 3-mercaptopropionitrile and by-products are recovered by vacuum distillation. 3'-y-ocypropionitrile was obtained. The results are summarized in Table-5.

Table-5 4)-7 Crylonitrile Hose Example 6 The same apparatus as in Example 1 was prepared. In a 1-liter reaction tank, 85.6 parts of sodium hydrosulfide (purity of sodium hydrosulfide: 72.0% by weight, the balance being water) was dissolved in 100 parts of methanol, and the mixture was maintained at 20°C.

While stirring, 91.2 parts of carbon disulfide was immediately added dropwise, and then 6 parts of methacriconitrile were slowly added dropwise. In this reaction, the temperature of the reaction solution increased due to exothermic reaction, so when the reaction temperature was maintained at 20° C. by external cooling, the reaction solution gradually crystallized from an orange solution and became a slurry. After the completion of the dropwise addition of methacrylonitrile, stirring was continued at 20° C. for about 3 hours, and then 300 parts of 15% by weight hydrochloric acid was added dropwise.

When the pH of the aqueous layer of the reaction solution reached 2, the dropping of hydrochloric acid was stopped. The reaction solution was separated from the top into two layers, an aqueous layer and an organic layer, and these were separated into two layers, an aqueous layer and an organic layer, using a separating funnel. After drying by adding a desiccant (anhydrous sodium sulfate) to the organic layer, carbon disulfide was recovered by atmospheric distillation, and then 3-mercapto-2-methylpropionitrile and the by-product 3,31-thiobis( 2-methylpropionitrile)
I got it.

The distillation results are summarized in Table 6.

Table 6 ”) Taku IJ Nitrile Base Procedural Amendment (Method) March 10, 1980 Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of Case 1982 Patent JLIQ No. 20613
No. 5 No. 2, Title of the invention Process for producing 3-mercaptopropionitrile or its 2-methyl substituted product 3, Relationship with the case of the person making the amendment Patent applicant address 5-1 Marunouchi-chome, Chiyoda-ku, Tokyo Name ( 3
95) 8 Tokagaku Kogyo Co., Ltd. Representative Masahiko Namba 4, Agent 158 Telephone 03 (720) 5
058 No. 6, Subject of amendment 1. Title of the invention
Column 7, Contents of amendment The second to fourth lines of page 1 of the specification are amended as follows.

Record ■9 Name of invention

Claims (1)

[Claims] 2,3-unsaturated propionitrile CH2=C-CN (1) represented by the following general formula (1) (wherein R is hydrogen or a methyl group) is converted into carbon disulfide. A method for producing 3-mercaptopropionitrile or its 2-methyl substituted product, which comprises reacting with an alkali sulfide or alkali hydrosulfide in the coexistence of 3-mercaptopropionitrile or an alkali hydrosulfide, and then treating with an acid.