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:
Jan. 09, 2007
Filed:
Aug. 16, 2005
Hari Babu Sunkara, Hockessin, DE (US);
Howard C. NG, Kingston, CA;
Wei Zheng, Kingston, CA;
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
A process of manufacture of polytrimethylene ether glycol comprising: (a) polycondensing reactant comprising diol selected from the group consisting of 1,3-propanediol, 1,3-propanediol dimer and 1,3-propanediol trimer or mixtures thereof in the presence of acid polycondensation catalyst to form polytrimethylene ether glycol; (b) adding water to the polytrimethylene ether glycol and hydrolyzing the acid esters formed during the polycondensation to form a hydrolyzed mixture containing the polytrimethylene ether glycol and the hydrolyzed acid esters; (c) adding organic solvent that is miscible with water to the hydrolyzed mixture to form an aqueous-organic mixture comprising (i) organic phase containing polytrimethylene ether glycol and residual acid polycondensation catalyst from the polycondensing and (ii) water phase; (d) separating the water phase and the organic phase; (e) adding base to the separated organic phase to neutralize the residual acid polycondensation catalyst by forming salts of the residual acid polycondensation catalyst; (f) separating the organic phase into (i) liquid phase comprising the polytrimethylene ether glycol, the organic solvent and any residual water, and (ii) solid phase comprising the salts of the residual acid polycondensation catalyst and the base which is unreacted; and (g) removing the organic solvent and the residual water from the organic phase to obtain polytrimethylene ether glycol.