PROCESS FOR ESTERIFYING 1,3-PROPANEDIOL

摘要

A process that can be used in an esterification and polycondensation processes to produce a polyester such as, for example, poly(trimethylene terephthalate) is disclosed. The process comprises contacting an acid with 1,3-propanediol in the presence of a catalyst comprising tin and titanium. A copolymer that contains up to 20 mole percent of another acid and/or a second alcohol is also disclosed. Further disclosed are a composition of, or comprising, a bis(3-hydroxypropyl) terephthalate prepolymer or a composition of, or comprising, a poly(trimethylene terephthalate) polymer. The bis(3-hydroxypropyl) terephthalate prepolymer and poly(trimethylene terephthalate) can each contain 10 to 100 ppm tin and 10 to 200 ppm titanium relative to the terephthalic acid content.