is disclosed wherein an anhydride of a carboxyaromatic such as pyromellitic dianhydride is reacted with a fluorinated alcohol and an epoxide to give a mixed ester capable of imparting oil and or water repellency to textiles the improvement comprises utilizing the epoxide as the reaction medium to reduce reaction times and waste water treatment requirements application_number US 35581282 A description the essence of applicants 39 invention is the discovery that the double esterification of carboxyaromatics by fluorinated alcohols and epoxides which has heretofore been carried out in two steps in various solvents may be advantageously conducted in one step without added solvent when the epoxide selected for the esterification is a liquid under the reaction conditions employed the liquid epoxide which is normally used in excess to drive the reaction to completion serves to keep the reaction mixture fluid and homogeneous thus the applicants 39 process comprises intimately mixing an anhydride of a carboxyaromatic a fluorinated alcohol and a liquid epoxide and heating said mixture to esterify said carboxyaromatic the carboxyaromatic anhydrides which can be employed in the process of this invention may be derived from any polycarboxyaromatic wherein one or more adjacent pairs of carboxyl groups have been converted to the anhydride the carboxyaromatics of general interest are the one and two ring aromatics such as benzene naphthalene pyridine pyrazine quinoline indole thiophene furan etc substituted by two or more carboxyl groups.