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:
May. 16, 1989
Filed:
Dec. 24, 1986
Masayoshi Hinenoya, Arai, JP;
Mamoru Endo, Arai, JP;
Daicel Chemical Industries, Ltd., Sakai, JP;
Abstract
The present invention provides (1) a process for producing a colorless aromatic acid anhydride having a high purity in a high yield by reacting an aromatic carboxylic acid having a carboxyl group bonded to the aromatic nucleus with a lower aliphatic acid anhydride in the presence of at least one metal ion selected from the group consisting of ions of metals of Groups, I, II, III, V, VII and VIII of the periodic table and (2) a process for producing an acid anhydride by an exchange reaction of an organic carboxylic acid anhydride and a carboxylic acid in the presence of at least 5 ppm of at least one metal ion selected from the group consisting of Co, Ni, Mn, Fe, Li, Na, K, Mg, Ca, Cu, Zn, Al, Ti and V ions.