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:
Feb. 12, 1991
Filed:
Mar. 05, 1990
Donald O Hutchinson, Baton Rouge, LA (US);
Ali M Dadgar, Baton Rouge, LA (US);
Keith G Anderson, Baton Rouge, LA (US);
Ethyl Corporation, Richmond, VA (US);
Abstract
In a first embodiment this invention relates to a process for preparing a white product which principally contains a bisimide. The process comprises: providing tetrabromophthalic anhydride and a solvent in a reaction vessel; forming, at a temperature within the range of from about 140.degree. C. to about 200.degree. C., a reaction mass by adding a diamine, a diamine salt or a mixture thereof to the solution, the formation of the reaction mass resulting in the production of a bisimide precipitate which becomes a component of the reaction mass; terminating the addition of the diamine when the molar ratio of the tetrabromophthalic anhydride initially present in the solution to the diamine or diamine salt added is substantially stoichiometric; cooking the bisimide precipitate to increase the average sphericity of the particles making up the bisimide precipitate; and recovering from the reaction mass, as the bisimide product, the cooked precipitate. In a second embodiment the cooking step is optional and the retention of water formed during the diamine or diamine salt addition is featured.