Esters are usually prepared by the acid-catalyzed reaction of alcohols and phenols with acids or acid derivatives, such as acid chlorides and anhydrides. In the presence of the reaction products, the esterification step is followed by the similar acid-catalyzed homogeneous hydrolysis of the polymer. Both the formation of the polymer and the hydrolysis reaction that follows are accompanied by considerable degradation of the polymer chain leading to deterioration of the polymer end-use properties.