1,2,4-Trichlorobenzene → 2,4,5-Trichlorobenzenesulphonic acid

Participants

Reaction Conditions

Reaction Steps

119 g (1.0 mol) of technical grade chlorosulfonic acid were added dropwise, under stirring, to 218 g (1.2 mol) of technical grade 90% strength 1,2,4-trichlorobenzene over a period of time of about one hour. The reaction was permitted to proceed at 150° to 160° C. for three hours. During the reaction a slow stream of dried air or dried carbon dioxide was passed through the reaction mixture. The resulting hydrogen chloride of reaction was transferred with the gas stream into a receiving flask containing water. The hydrochloric acid trapped in the receiving flask constituted about 96% of theoretical. The reaction mixture, after being cooled to 120° C., was mixed with 200 ml of water. Steam was then charged therein to remove excess trichlorobenzene. 37 g (0.2 mol) of trichlorobenzene were recovered. Water was added to the reaction mixture to provide a total volume of 700 g which was then titrated with sodium hydroxide solution.

Provenance & Evidence