Patent ID: 6872848

Claim:
A process for the preparation of esters of polyalkylene glycols, said glycols being endcapped at one end, with monoethylenically unsaturated carboxylic acids or anhydrides comprising esterifying (a) monoethylenically unsaturated carboxylic acids or anhydrides with (b) polyalkylene glycols which are endcapped at one end, in the absence of a solvent and in the presence of polymerization inhibitors and esterification catalysts, at not more than 160° C., wherein the esterification is first carried out under atmospheric pressure or at up to 50 bar, wherein the water formed in the esterification is then distilled off from the reaction mixture at from 10 to 500 mbar, and wherein the esterification is then continued under atmospheric pressure or at up to 50 bar, where the esterification is additionally carried out at from 100 to 140° C. up to the equilibrium reaction, wherein the pressure is then reduced to 50 to 200 mbar in order to remove from the reaction mixture the water formed in the esterification, and wherein the reaction mixture is then esterified again at from 100 to 140° C. under atmospheric pressure or at up to 50 bar until the equilibrium reaction is established.