Thionyl Chloride → Toluene-p-sulphonic anhydride

Participants

Reaction Conditions

Reaction Steps

50.0 g (260 mmol) of p-toluenesulphonic acid monohydrate were suspended in 140 g of methylcyclohexane and heated to 50° C. with stirring. 99.9 g (831 mmol, 3.2 equivalents [eq.]) of thionyl chloride were then added dropwise over a period of 75 minutes at such a rate that moderate gas evolution was observed. After addition had ended, the mixture was stirred at 50° C. for a further 1 h. 20.1 g of excess thionyl chloride were then distilled off at a bottom temperature of 96° C. The residue was cooled to 5° C. and stirred at this temperature for 1 h. The precipitated solid was filtered off and washed with 50 ml of methylcyclohexane. After drying under reduced pressure, 22.2 g (52% of theory) of p-toluenesulphonic anhydride were isolated.

Provenance & Evidence