Claims
- 1. 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.
- 2. The process of claim 1 wherein the molar ratio of N-aminoimide to tetrabromophthalic anhydride is within the range of from about 2:1 to about 1:1.
- 3. The process of claim 1 wherein the reaction mass is maintained at a temperature within the range of from about 110.degree. C. to about 300.degree. C.
- 4. The process of claim 1 wherein the reaction medium is concentrated sulfuric acid or oleium.
- 5. The process of claim 4 wherein said hydrazine is provided as a solution of hydrazine sulfate in concentrated sulfuric acid.
- 6. The process of claim 4 wherein the concentrated sulfuric acid is from about 90% to about 100% sulfuric acid in aqueous solution.
- 7. The process of claim 4 wherein the reaction mass is maintained at a temperature within the range of from about 110.degree. C. to about 300.degree. C.
- 8. The process of claim 4 wherein the molar ratio of N-aminoimide to tetrabromophthalic anhydride is within the range of from about 2:1 to about 10:1.
- 9. The process of claim 1 wherein the reaction mass is formed from about 1.67 to about 1.25 moles of tetrabromophthalic anhydride per mole of hydrazine or hydrazine providing compound used in forming the reaction mass.
- 10. The process of claim 1 wherein said period of time is up to about 20 hours.
- 11. The process of claim 1 wherein the aqueous basic solution is a NaOH, a KOH, an NH.sub.4 OH, or a Na.sub.2 CO.sub.3 solution.
- 12. The process of claim 1 wherein the so contacted product is recovered by centrifugation.
- 13. The process of claim 1 further comprising washing the separated product from step (c) prior to step (d).
Parent Case Info
This application is a division of application Ser. No. 07/530,112, filed May 29, 1990now U.S. Pat. No. 5,076,970.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4720553 |
Lee et al. |
Jan 1988 |
|
4894187 |
Bonnet et al. |
Jan 1990 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
530112 |
May 1990 |
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