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:
Aug. 17, 1976
Filed:
Sep. 28, 1973
Applicant:
Inventor:
Maurice Balme, Sainte-Foy-les-Lyon, FR;
Assignee:
Rhone-Poulenc S.A., Paris, FR;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
26032626 ; 260691 ;
Abstract
An improved process for the dehydration of bis-maleic acids to bis-maleimides is provided which comprises heating the bis-maleamic acid with a lower carboxylic acid anhydride in acetone, in the presence of 0.2 to 1 mol of tertiary amine per mol of bis-maleamic acid and of a soluble nickel derivative and 0.1 to 10 mols of water per mol of bis-maleamic acid and precipitating the resulting bis-maleimide by the addition of water. The addition of water to the starting materials reduces the proportion of by-products produced and increases the degree of cyclodehydration.