Catalyst system for producing polyethylene terephthalate from a lower dialkyl ester of a dicarboxylic acid and a glycol.

摘要

A catalyst composition, and a process for using it to produce polyester is described. 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 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. Both the ester interchange rate and the polymerization rate are increased as compared to more conventional systems for producing polyester.