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. 05, 1999
Filed:
Nov. 26, 1997
Suriyanarayan Dorai, Missouri City, TX (US);
Donald Truszkowski, Kingwood, TX (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
An improved method for manufacturing diesters of polytetramethylene ethers involving the polymerization of tetrahydrofuran (THF) optionally with one or more comonomers (e.g., 3-methyl THF, ethylene oxide, propylene oxide, or the like) utilizing a solid acid catalyst (e.g., Nafion.RTM.) and a carboxylic acid with carboxylic acid anhydride (e.g., acetic acid with acetic anhydride) as molecular weight control agents wherein setting the pressure of the reactor while simultaneously achieving removal of the heat of reaction by operating under solvent/monomer evaporative reaction conditions effectively controls the reaction temperature. Such a process is useful in producing high purity commercial grade PTMEA that advantageously avoids problems caused by the high heat of reaction when such a process is scaled up to commercial level.