CS231245B1 - A method for producing 2-amino-2-methylpropionitrile - Google Patents

Abstract

A method for producing 2-amino-2-methylpropionitrile of formula I by reacting 2-oxy-2-methylpropionitrile with gaseous ammonia in an autoclave for 10 hours, with the water of reaction being removed from the reaction mixture before distillation of the product. The reaction is carried out at a pressure of 0.8 to 1.0 MPa and a temperature of not more than 65°C achieved by the released heat of reaction.

Description

The invention relates to a process for the preparation of 2-amino-2-methylpropionitrile by reacting 2-oxy-2-methylpropionitrile with ammonia gas in an autoclave without cooling or heating the reaction mixture at a pressure of 0.8 to 1.0 MPa.

Pressure methods for preparing 2-amino-2-methylpropionitrile by reacting 2-oxy-2-methylpropionitrile with ammonia are known in the literature. U.S. Pat. No. 3,505,325 (1970) discloses the reaction of 2-oxy-2-methylpropionitrile with liquid ammonia in an autoclave at a temperature of up to 40 ° C, followed by heating the reaction mixture at 50 ° C for 3 hours. The yield of distilled product is 68%. US Pat. No. 3,821,220 (1974) discloses the preparation of 2-amino-2-methyl-propionitrile from 99% 2-oxy-2-methylpropionitrile and ammonia in an autoclave while cooling the reaction mixture to 5-10 ° 0 by maintaining the reaction for 8 hours of mixture at 20-25 ° C. Jap. pat.

090 232 (1974, ref. Derwent Publications 76, 25 '63 / x) describes the preparation of 2-amino-2-methylpropionitrile from 2-oxy-2-methylpropionitrile and ammonia in an autoclave at 25 ° C for 10 hours. 92% of theory.

It has now become golden that it is possible to produce 2-amino-2-methylpropionitrile of formula i.

by reaction of 2-oxy-2-methylpropionitrile with ammonia gas according to the reaction scheme

in an autoclave for 10 hours, the reaction water being removed from the reaction mixture prior to distillation of the product according to the invention.

The principle of the invention is that the reaction is carried out at a pressure of 0.8 to 1.0 MPa, without removing the heat of reaction from the reaction mixture with a cooling medium, and also without heating the reaction mixture at the time of reaction completion. The temperature of the reaction mixture does not exceed 65 ° C and is achieved by the released reaction heat.

The advantage of the process for the preparation of 2-amino-2-methylpropionitrile according to the invention is mainly in saving the energy required for cooling or heating the reaction mixture and in a higher yield of the product obtained.

The following example illustrates but does not limit the scope of the invention.

Example 1

85.1 g (0.1 mol) of 96% 2-oxymethylpropionitrile were charged to a 220 ml reactor. The ammonia gas was pressurized from the pressure vessel to rise to 1.0 MPa. A grinding machine was started, the temperature of the reaction mixture rising from about 20 ° C to 58 ° C in 30 minutes. The pressure dropped to 0.6 MPa and adjusted to 0.8 MPa by addition of ammonia. After reaching a maximum temperature of 58 ° C, the temperature of the reaction mixture began to fall and reached about 20 ° C in about 1.5 hours. Stirring was continued at ambient temperature for an additional 8 hours. Excess ammonia was then discharged from the reactor and the reaction mixture, which absorbed a total of 26 g (1.52 mol) of ammonia, was transferred to a separatory funnel. Here, 10 g of solid potassium hydroxide was shaken twice to produce ammonia. The separated aqueous alkaline layer was separated each time and the reaction water was removed, and the crude product was distilled off.

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79.5 g of distilled product were obtained, boiling point 49-50 [deg.] C. (1.99 kPa β containing 96.60% of 2-amino-2-methylpropionitrile. The yield was 95.10% of theory, calculated on 2-oxy-2). -metylpropíonitril.

Claims (1)

A process for the preparation of 2-amino-2-methylpropionitrile of formula I by reaction of 2-oxy-2-methylpropionitrile and ammonia gas in an autoclave for 50 hours, wherein the reaction water is removed from the reaction mixture prior to distillation of the product. . at a pressure of 0.8 to 1.0 MPa and a temperature of not more than 65 ° C obtained by the released reaction heat.