Preparation of glycol carboxyethylmethylphosphinate

Abstract

The invention relates to a process of preparing glycol carboxyethylmethylphosphinate, which comprises a) reacting elemental yellow phosphorus with methyl chloride in the presence of an alkali or alkaline earth metal hydroxide to form a mixture which includes the alkali and/or alkaline earth metal salts of methylphosphonous, phosphorous and hypophosphorous acids as main constituents, b) esterifying the methylphosphonous acid from the mixture obtained by a), c) removing the methylphosphonous ester from the mixture, d) adding the thus obtained methylphosphonous ester to an acrylic ester, e) hydrolyzing the diester thus obtained, f) esterifying the resulting carboxyethylmethylphosphinic acid with ethylene glycol directly to the glycol carboxyethylmethylphosphinate. The invention also relates to the use of the glycol carboxyethylmethylphosphinates prepared according to the invention as reactive flame retardants for polymers.

Dependencies are inferred from the claim text.