PROCESS FOR PREPARING AROMATIC POLYESTERS

In an improved process for the preparation of aromatic polyesters by polycondensation of diphenols with aromatic dicarboxylic acid halides such as isophthalic acid chloride and/or terephthalic acid chloride, by a two-phase interface polycondensation method wherein a fine dispersion is produced from an aqueous phase consisting of a solution of diphenol, alkali metal hydroxide for the formation of the alkali metal diphenolate in a stoichiometric ratio or in a slight excess and a phase transfer catalyst like triethylbenzylammonium chloride, tetrabutyl ammonium iodide or crown ether in a mixture of water and an organic solvent as a solubilizer with the organic liquid phase consisting of a solution of the acid chloride in a halogenated solvent, where the diphenolate, transferred to the liquid phase by the phase transfer catalyst, reacts with the acid chloride in a polycondensation reaction for the formation of the polyester, and the polyester formed remains dissolved in the organic phase the improvement comprising using as the solubilizer an alkanol of 2 to 5 carbon atoms or an alkoxy alkanol of 2 to 5 carbon atoms and polyester esters produced thereby.