Patent ID: 7851656

Claim:
A method of producing compounds of the formula XPR 2 (OR 1 ) Ia where X is chlorine, bromine or iodine and R 1 is an organic radical which comprises reacting a compound of the a formula X 2 PR 2 II, in which X has the meaning given above and R 2 is an organic radical, with a compound of the formula R 1 OH III, in which R 1 has the meaning given above, to give a mixture IV, wherein a) the postreaction is carried out at a temperature of from 50 to 240° C. and a pressure of from 0.001 to 0.9 bar, b) from the mixture IV the compound Ia is separated off from the compound PR 2 (OR 1 ) 2 Ib and, optionally the compounds II and c) compounds Ib and optionally unreacted compounds II are returned to the synthesis stage.