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. 17, 2006
Filed:
Feb. 16, 2001
Applicants:
Seiji Nishioka, Hyogo, JP;
Ryosuke Maeda, Hyogo, JP;
Toshifumi Fukui, Hyogo, JP;
Mitsuru Yamashita, Hyogo, JP;
Inventors:
Seiji Nishioka, Hyogo, JP;
Ryosuke Maeda, Hyogo, JP;
Toshifumi Fukui, Hyogo, JP;
Mitsuru Yamashita, Hyogo, JP;
Assignee:
Primary Examiner:
Int. Cl.
CPC ...
C07C 51/573 (2006.01); C07C 41/01 (2006.01); C07C 41/34 (2006.01); C07C 41/42 (2006.01); C07C 43/04 (2006.01);
U.S. Cl.
CPC ...
Abstract
The present invention provides acetic anhydride, a method of purifying crude acetic anhydride, and a method of producing polyoxytetramethylene glycol using acetic anhydride. A method of producing polyoxytetramethylene glycol by ring-opening-polymerizing tetrahydrofuran in the presence of acetic anhydride and an acid catalyst, wherein said ring-opening polymerization is conducted using acetic anhydride having a diketene concentration of 10 ppm or less to produce polyoxytetramethylene glycol.