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:
Jun. 11, 2002
Filed:
Jan. 13, 2000
Mitsuharu Kobayashi, Kanagawa, JP;
Nobuyuki Murai, Mie, JP;
Mitsubishi Chemical Corporation, Tokyo, JP;
Abstract
Disclosed are a process for producing a poly(alkylene ether) glycol which comprises polymerizing a cyclic ether in the presence of at least a catalyst and a carboxylic acid anhydride, wherein the carboxylic acid anhydride has a ketene dimer content of 50 ppm or lower, and a process for producing a poly(alkylene ether) glycol which comprises polymerizing a cyclic ether in the presence of at least a catalyst and acetic anhydride, wherein the acetic anhydride is purified acetic anhydride obtained by treating acetic anhydride by contacting with at least one of a metal oxide and a mixed oxide, and optionally, distilling the acetic anhydride simultaneously with or after the contact treatment.