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:
Jul. 24, 1990
Filed:
Jun. 08, 1989
Andrzej Rokicki, Alburtis, PA (US);
Air Products and Chemicals, Inc., Allentown, PA (US);
Arco Chemical Company, Newtown Square, PA (US);
Mitsui Petrochemical Industries, Ltd., Tokyo, JP;
Abstract
Poly(alkylene carbonates) of controlled molecular weight are made by copolymerizing carbon dioxide and one or more oxirane compounds using zinc polycarboxylate catalyst in the presence of a sterically hindered organic proton donor. The acidity of the donor is in the range of 3 to 20 pK.sub.a and the steric quality of the donor is such that it has a steric parameter (E.sub.s) of -0.38 or less. The molecular weight of the polymer can be regulated by altering the level of proton donor over a range which does not adversely affect catalyst productivity. Benzoic acid and phenol are examples of suitable proton donors. The preferred catalyst is one made from zinc oxide and a dicarboxylic acid, such as glutaric acid or adipic acid.