such as oxalic malonic succinic glutaric adipic pimelic suberic azelaic sebacic maleic fumaric the aromatic dicarboxylic acids such as phthalic isophthalic terephthalic the alkylene glycols such as ethylene glycol and propylene glycol alkanols such as 1 4 butanediol the polyalkylene glycols such as polyethylene glycol polybutylene glycol and polypropylene glycol polyols such as glycerol polyglycerol trimethylolpropane sorbitol glucose and sucrose pentaerythritol and aerythritol phenols such as hydroquinone resorcinol and bisphenol a alkanolamines such as ethanolamine diethanolamine and triethanolamine and amines such as the aromatic amines aniline and phenylene polyamine and the aliphatic amines such as ethylene diamine and diethylene triamine any polybasic acid can be used in the preparation of the polyoxyalkylene esters employed in accordance with the present invention illustrative acids include inorganic acids such as phosphoric acid phosphorus acid and boric acid aliphatic organic acids such as malonic acid succinic acid glutaric acid adipic acid maleic acid fumaric acid malic acid oxalic acid tartaric acid and diglycolic acid and aromatic organic acids such as phthalic acid terephthalic acid isophthalic acid trimellitic acid and mixtures thereof it will be understood that the anhydrides of any of the above acids where they exist can be used alternatively to the use of the acids in the preparation of the esters of the invention in the preparation of the polyoxyalkylene esters which are employed in accordance with the present invention it is preferred to employ at least equal molar amounts of acids or their anhydrides or an excess of that required for complete esterification of the polyols thus for example one mole of a polyol is prepared by reacting 1 2 butylene oxide.