Thionyl Chloride → Toluene-p-sulphonic anhydride

Participants

Reaction Conditions

Reaction Steps

150.0 g (789 mmol) of p-toluenesulphonic acid monohydrate were suspended in 360 g of cyclohexane and heated to 50° C. with stirring. 240.0 g (1997 mmol, 2.6 eq.) of thionyl chloride were then added dropwise over a period of 190 min at such a rate that moderate gas evolution was observed. After addition had ended, the mixture was stirred at 50° C. for a further 0.5 h. 80 g of excess thionyl chloride/cyclohexane were then distilled off at a bottom temperature of 71-76° 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 150 ml of cyclohexane. After drying under reduced pressure, 70.5 g (53% of theory) of p-toluenesulphonic anhydride were isolated.

Provenance & Evidence