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:
Apr. 06, 1976
Filed:
Oct. 29, 1974
Applicant:
Inventor:
Kurt Handrick, Essen, DT;
Assignee:
Bergwerksverband GmbH, Essen, DT;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
2603463 ;
Abstract
Commercial grade crude trimellitic acid anhydride containing free trimellitic acid and other impurities is purified by forming a suspension of the trimellitic acid anhydride in a mixture of acetic acid anhydride, acetic acid and benzene at a temperature of about the boiling point of the mass, the acetic acid anhydride being used in an excess up to about 200% by weight over the stoichiometric amount and the benzene being used in an amount up to 6 times the weight of the anhydride and recovering the purified trimellitic acid anhydride from the mass.