Process for making phosphonic acid ester chlorides

摘要

The disclosure relates to a process for making phosphonic acid ester chlorides of the general formula (I) R-P(O) ClOR'(I) in which R stands for an alkyl group with 1 to 6 carbon atoms or an aryl group and R' stands for an alkyl group with 1 to 20 carbon atoms or an aryl group. More particularly, a compound of general formula (II) R-PCl2 (II) is reacted with a sulfuric acid monoester of general formula (III) R'-O-SO3H (III) R and R' in formulae (II) and (III) having the meanings given above; the reactants are used in about equimolar proportions and the reaction is effected at a temperature of from -20 DEG C. to 50 DEG C. After termination of the reaction, the phosphonic acid ester chloride is separated from the reaction mixture by subjecting this latter to distillation under vacuum.