The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 17, 1995
Filed:
Feb. 27, 1995
Donald R Kelsey, Fulshear, TX (US);
Charles C-S. Chou, Houston, TX (US);
Shell Oil Company, Houston, TX (US);
Abstract
A process for preparing a 1,3-propanediol-based polyester comprises contacting an aqueous stream containing acrolein byproduct with a base for a time effective to reduce the acrolein content of the aqueous stream. In a specific embodiment, a poly(propylene terephthalate) preparation process comprises the steps of: (a) contacting 1,3-propanediol and 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 about 7.5 and maintaining the basic solution 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 for a time effective to further lower the acrolein content. The process of the invention provides a polyester byproduct stream containing reduced levels of acrolein.