Process for the preparation of 2,2,2-trichloro-1-hydroxymethyl phosphonic acid diesters

Abstract From the Canadian patent

A process for the preparation of 2,2,2-trichloro-1-hydroxyethyl phosphonic acid esters, typically the dimethyl ester known as trichlorfon, wherein a three stage reaction is used without, isolating the intermediate products and wherein the reactants taken, for the process are phosphorus trichloride an alkanol (which can be, phenol), water and trichloroacetaldehyde. The reaction is carried out in a hydrocarbon, typically benzene at a temperature of about, 80°C. The presence of the water both moderates the reaction and, substantially reduces the formation of methylchloride as a byproduct.