Patent ID: 6657077
Filing Date: 2003-12-02
Classification: C07C,C08J,Y02W

Abstract:
A process for producing an alkali metal aromatic dicarboxylate and an alkylene glycol from a polyester of an aromatic dicarboxylic acid derived from a dicarboxylic acid forming a soluble salt with alkali metal comprising the steps of:carrying out an alkaline saponfication by reacting said polyester with an alkali metal hydroxide in a liquid medium at a reaction temperature in the range of about 120Â° C. to the boiling point of the corresponding alkylene glycol; adding a volume of water which is sufficient to ensure dissolution of all of the alkali metal aromatic dicarboxylate produced in the liquid phase of the reaction medium; concentrating the solution by evaporating off water to cause a major portion of the alkali metal dicarboxylate to crystallize out of the liquid phase then charged with alkylene glycol, wherein the step of concentrating the solution by evaporating off water comprises crystallizing the alkali metal dicarboxylate out of the solution at a temperature of 50Â° C. to 90Â° C. under partial vacuum; and recovering said alkali metal aromatic dicarboxylate and said alkylene glycol.