BYPRODUCT STREAM PURIFICATION IN THE PREPARATION OF 1,3-PROPANEDIOL-BASED POLYESTERS

摘要

A process for preparing a 1,3-propanediol-based polyester which comprises contacting an aqueous stream containing acrolein byproduct with a base for a time effective to reduce the acrolein content of the aqueo us stream. In a specific embodiment, a poly(propylene terephthalate) preparation process comprises the steps of (a) contacting 1,3-propanediol an d terephthalic acid at elevated temperature to produce a reaction product mixture comprising a poly(propylene terephthalate) and an aqueous solution comprising acrolein; (b) removing a major portion of the aqueous solution from said reaction product mixture; (c) adding a sufficient quantity of a base to the aqueous solution to form a basic solution having a pH greater than 7.5 and maintening the basic solutio n for a time effective to lower the acrolein content thereof (d) optionally diluting the basic solution with water, and (e) optionally, biotreating the dilute basic solution. The process of the invention provides a polyester byproduct stream containing reduced levels of acrolein.