Reduction of hydrolyzable chloride impurities in an isocyanatoalkyl ester of an organic carboxylic acid

Claim 1

In a process for preparing an isocyanatoalkyl ester of an organic carboxylic acid represented by the formula ##STR6## wherein each R is independently hydrogen, alkyl, alkenyl, alkoxy, alkaryl, aralkyl or aryl; R' is hydrogen, C 1 -C 17 alkyl, C 2 -C 17 alkenyl, C 7 -C 20 alkaryl or C 6 -C 24 aryl and n is 2 or 3, said process comprising the steps of reacting a 2-oxazoline or 2-oxazine with phosgene in a water-immiscible, organic solvent in the presence of an aqueous solution of a hydrogen chloride acceptor and then separating the organic solution of the resulting isocyanatoalkyl ester from the aqueous phase, the improvement comprising the steps of: (a) contacting the isocyanatoalkyl ester in a liquid phase with a vicinal epoxide-containing compound, said epoxide-containing compound being present in a ratio of at least about 0.5 equivalent of epoxide per equivalent of hydrolyzable chloride, so as to effect substantial reaction of the epoxide-containing compound with the hydrolyzable chloride; and (b) separating the isocyanatoalkyl ester from the other components of the liquid mixture resulting from Step (a) by fractional distillation.