Prepn. of phosphorous ester contg. lower alkyl gps. - by reaction of phosphorus tri:chloride with alkanol(s) used as intermediate e.g. for phytosanitary prods.

摘要

Phosphorous esters contg. 1-4C alkyl gps. esp. dialkyl phosphites, are prepd. by reaction of PCl3 and the 1-4C alkanol, by mixing PCl3, alkanol and a solvent which is benzene, benzene homologue, halogenated benzene or a halogenated 1-4c aliphatic hydrocarbon and allowing these to react in a vessel in which liquid and vapour are in equilibrium in areas of graded temps., there being a reaction zone at 45-110 degrees C in which the mixt. is kept until there is total transformation of starting material, a distn. zone at 10-70 degrees C and a distn. zone at 10-25 degrees C in which CHl and alkyl chlorides formed are sepd. from dialkyl phosphite, and a base zone at 70-135 degrees C from which dialkyl phosphite and solvent are removed. The prods. are intermediate for phytosanitary products (insecticides, herbicides, etc.). Process gives better yields with less by-products.