反应详情

温度

25 °C

100 g (0.5 mol) of 4-chloro-3-nitrobenzoic acid, 36 g (0.6 mol) of urea and 0.5 g of phosphorous acid are heated in 250 ml of 1,2-dichlorobenzene with stirring at from 165° to 178° C. for 8 h. After cooling to 25° C. the solid is filtered off with suction and washed with 50 ml of 1,2-dichlorobenzene. The filter cake is introduced into 250 ml of water, and the mixture is adjusted to a pH of 12 using aqueous sodium hydroxide solution and subjected to steam distillation. Subsequently the solid is filtered off with suction and dried at 100° C. 89.7 g of 4-chloro-3-nitrobenzamide are obtained having a melting point of from 146° to 149° C. This corresponds to a yield of 90.2% of theory. By acidification of the aqueous mother liquor to pH 2, 4.9 g of 4-chloro-3-nitrobenzoic acid (4.9% of theory) are obtained, which can be employed again in a subsequent batch.

1. filtrationis filtered off with suction
2. washwashed with 50 ml of 1,2-dichlorobenzene
3. additionThe filter cake is introduced into 250 ml of water
4. distillationsubjected to steam distillation
5. filtrationSubsequently the solid is filtered off with suction
6. customdried at 100° C