Hydrochloric Acid → HCID 13668876, compound

Participants

Reaction Conditions

Reaction Steps

158 g of the sodium salt of 4-chloro-4-nitro benzenesulphonic acid (technical, about 83% pure) are dissolved at about 80° C. in 400 ml of water. 180 ml of 30% strength aqueous sodium hydrogen sulphide solution (technical) are added dropwise in the course of about 30 minutes. The mixture is then stirred at 90° C. for one hour and is then cooled down to 70° C., and at at this temperature 93 g of 4-nitrobenzoyl chloride are added. The pH of the mixture is held at 8 by addition of sodium hydroxide solution. As soon as the pH remains constant, 180 ml of 30% strength aqueous sodium hydrogen sulphide solution are added, and the reaction mixture is boiled under reflux for one hour. The reaction mixture is then brought to pH 1 with hydrochloric acid and is boiled under reflux for 5 hours. After cooling down, the precipitated product is isolated. The crude product is heated to 90° C. in a mixture of 300 ml of water and 150 ml of 20% strength ammonia water. The mixture is filtered while still hot, and 50 g of sodium chloride are added to the filtrate while still hot. On cooling down, 125 g of pure product of the formula ##STR20## crystallise out.

Provenance & Evidence