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US 5,175,305 AGranted
Process for preparing N,N'-bis(tetrabromophthalimide)
AssigneeEthyl Corporation
InventorsJoseph W. Roos, Robert M. Moore, Jr.
Life of this patent
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Abstract
This invention relates to a process for preparing and treating a product predominant in N,N'-bis(tetrabromophthalimide) so as to produce a bisimide product which has enhanced suitability for use in thermoplastic formulations as a result of reduction in volatile impurities and particle size.
Claims13
The process for preparing a product in N,N'-bis-(tetrabromophthalimide), which process comprises:
- (a) forming a reaction mass from at least (i) tetrabromophthalic anhydride, (ii) hydrazine or a hydrazine providing compound, and (iii) a reaction medium;
- (b) maintaining the so-formed reaction mass at a temperature within the range of from about 40.degree. C. to about 300.degree. C. for a time sufficient to obtain a product predominant in N,N'-bis(tetrabromophthalimide);
- (c) separating the product from the reaction mass;
- (d) contacting the separated product with an aqueous basic solution;
- and
- (e) recovering the contacted product, said contacted product being comprised of a predominant amount of N,N'-bis(tetrabromophthalimide) and minor amounts of impurities which comprise tetrabromophthalate anhydride and N-aminoimide wherein the molar ratio of the N-aminoimide to tetrabromophthalate anhydride is within the range of from about 1.5:1 to about 100:1.
3 more elements
Dependencies are inferred from the claim text.