Ammonia → 2-Amino-3-chlorobenzoic acid

Participants

Reaction Conditions

Reaction Steps

191 parts of 2,3-dichlorobenzoic acid, 80 parts of 50% strength aqueous sodium hydroxide solution, 1004 parts of 25% strength aqueous NH3 solution and 5 parts of CuCl are initially introduced into a 2 l V4A autoclave. 89 parts of liquid NH3 (d20 : 0.61) are also forced in, and the autoclave is heated at 170° C. for 5 hours, during which the pressure drops from initially 25 bar to about 22 bar. When the reaction has ended, the contents of the autoclave are cooled to 25° C. and the autoclave is emptied via the ascending line. The reaction solution is boiled under reflux until a bottom temperature of 100° C. is reached, and the NH3 gas driven off is collected in a waste gas washer. After cooling to 25° C., the reaction solution is brought to pH 3 with 122 parts of 30% hydrochloric acid. The 2-amino-3-chlorobenzoic acid which has precipitated is filtered off with suction, washed with 300 parts of water and dried at 80° C. in vacuo. 145 parts (85% of theory) of 2-amino-3-chlorobenzoic acid of melting point 185° to 187° C. are obtained.

Provenance & Evidence