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. 02, 1985
Filed:
Oct. 29, 1984
Visweswara R Durvasula, Cheshire, CT (US);
The Upjohn Company, Kalamazoo, MI (US);
Abstract
A method is described for autoxidizing ortho-dialkyl substituted aromatic ethers directly to their corresponding carboxylic acid anhydrides. The method comprises autoxidizing the ethers in a first step in a solution of an aliphatic monocarboxylic acid having 2 to 8 carbon atoms to form a partially oxidized reaction mixture. The autoxidation of the partially oxidized mixture is continued in a second step after the addition of an anhydride of an aliphatic monocarboxylic acid having 3 to 8 carbon atoms and at a temperature of at least 130.degree. C. to form said anhydrides. The anhydrides are used in the preparation of organic high temperature polymers such as polyamideimides, polyimides, polyetherimides, and polyetherimideamides.