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:
Dec. 22, 1998
Filed:
Dec. 14, 1995
Suriyanarayan Dorai, Missouri City, TX (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
A method for converting the diester of a polyether polyol (e.g., the diacetate ester of polytetramethylene ether, PTMEA) to a corresponding dihydroxy polyether polyol (e.g., polytetramethylene ether glycol, PTMEG) involving reactive distillation wherein a diester of polyether polyol is fed to the top portion of the column along with an effective amount of at least one alkali metal oxide or alkaline earth metal oxide, hydroxide or alkoxide catalyst (e.g., sodium methoxide) and with a C.sub.1 to C.sub.4 alkanol (e.g., methanol) while simultaneously adding to the bottom of the reactive distillation column hot alkanol vapor to sweep any alkanol ester formed by alkanolysis of the diester of polyether polyol upwardly. Such a process is useful for achieving high levels of conversion PTMEA to PTMEG on a commercial scale with the overhead from the column being amenable to azeotropic separation of the methyl acetate and recycle of the methanol.