Dimethyl Sulfate → 3-(N-methylamino)aniline-4-sulfonic acid

Participants

Reaction Conditions

Reaction Steps

94 g of 1,3-diaminobenzene-4-sulfonic acid in 430 ml of water and 70 g of formic acid were boiled under reflux for 3 hours. Then, at 20° C., 100 ml of water were added and the pH was adjusted to 6.5 with caustic soda solution. 70 g of acetic anhydride were then added, the pH being kept between 5.5 and 6.5 with caustic soda solution. The pH was then adjusted to 12.5 with caustic soda solution, and 75 g of dimethyl sulfate were added. After 30 minutes, 110 g of 50% w/w caustic soda solution were added, and the mixture was boiled under reflux at 100° C. for 3 hours. 150 ml of water were then distilled off and the pH was adjusted to 1 with hydrochloric acid. At 20° C., the precipitated 3-(N-methylamino)aniline-4-sulfonic acid was isolated by filtration.

Provenance & Evidence