CATALYST SYSTEM FOR PRODUCING POLYETHYLENE TEREPHTHALATE FROM A LOWER DIALKYL ESTER OF A DICARBOXYLIC ACID AND A GLYCOL

摘要

A novel catalyst composition, and a process for using the novel catalyst system to produce polyester is described. The novel catalyst composition is specific for producing polyester from a lower dialkyl ester of a dicarboxylic acid and glycol, wherein the catalyst composition includes from about 20 ppm to about 150 ppm manganese; from about 50 ppm to about 250 ppm lithium; from about 10 ppm to about 40 ppm cobalt; and from about 200 ppm to about 400 ppm antimony, all amounts being based upon the expected yield of the polyester. The process for using the novel catalyst composition to make polyester includes the step of employing an effective catalytic amount of manganese and lithium in an ester interchange reaction from a lower dialkyl ester of a dicarboxylic acid and glycol to produce monomer; and using an effective catalytic amount of cobalt and antimony in the polycondensation reaction to convert the monomer to polyester. Using the novel catalyst composition or novel process to produce polyester drastically increases both the ester interchange rate and the polymerization rate, such that the ester interchange time and the polycondensation time are drastically reduced as compared to more conventional systems for producing polyester.