Claims
- 1. A process for the preparation of 3,4,6-trifluorophthalic acid which comprises
- A) reacting potassium fluoride with 3,4,6-trichloro-N-R-phthalimide at a temperature of about 200.degree. to 270.degree. Celsius under anhydrous conditions and in the absence of a catalyst to form 3,4,6-trifluoro-N-R-phthalimide wherein R is the same in each instance and is selected from the group consisting of C.sub.1-12 alkyl, phenyl, C.sub.1-12 monoalkyl phenyl, naphthyl and C.sub.1-12 monoalkyl naphthyl, and
- B) hydrolyzing the 3,4,6-trifluoro-N-R-phthalimide to form 3,4,6-trifluorophthalic acid.
- 2. A process according to claim 1 carried out in the presence of a solvent.
- 3. A process according to claim 2 carried out in the presence of a polar aprotic solvent.
- 4. A process according to claim 3 carried out at a temperature of about 220.degree. to 260.degree. Celsius.
- 5. A process according to claim 1 wherein R is phenyl.
- 6. A process according to claim 5 carried out at a temperature of about 220.degree. to 260.degree. Celsius.
- 7. A process according to claim 6 wherein the solvent is sulfolane.
- 8. A process according to claim 1 wherein R is methyl.
- 9. A process according to claim 8 carried out at a temperature of about 220.degree. to 260.degree. Celsius.
- 10. A process according to claim 9 wherein the solvent is sulfolane.
- 11. A process for the preparation of a trifluorophthalimide of the formula ##STR4## wherein R is selected from the group consisting of C.sub.1-12 alkyl, C.sub.1-12 monoalkyl phenyl, naphthyl and C.sub.1-12 monoalkyl naphthyl, which comprises reacting potassium fluoride with a trichlorophthalimide of the formula ##STR5## wherein R is as defined above, the process being carried out at a temperature of about 200.degree. to 270.degree. Celsius in the absence of a catalyst.
- 12. A process according to claim 11 carried out in the presence of a solvent.
- 13. A process according to claim 12 carried out in the presence of a polar aprotic solvent.
- 14. A process according to claim 13 for the preparation of 3,4,6-trifluoro-N-phenylphthalimide which comprises reacting potassium fluoride with 3,4,6-trichloro-N-phenylphthalimide.
- 15. A process according to claim 14 carried out at a temperature of about 220.degree. to 260.degree. Celsius.
- 16. A process according to claim 15 wherein the solvent is sulfolane.
- 17. A process according to claim 13 for the preparation of 3,4,6-trifluoro-N-methylphthalimide which comprises reacting potassium fluoride with 3,4,6-trichloro-N-methylphthalimide.
- 18. A process according to claim 17 carried out a temperature of about 220.degree. C. to 260.degree. C.
- 19. A process according to claim 18 wherein the solvent is sulfolane.
- 20. 3,4,6-Trifluoro-N-phenylphthalimide.
- 21. 3,4,6-Trifluoro-N-methylphthalimide.
Parent Case Info
This application is a continuation-in-part of U.S. application Ser. No. 07/653,554 filed Feb. 11, 1991 now abandoned (a division of U.S. application Ser. No. 07/315,746, filed Feb. 27, 1989 now U.S. Pat. No. 5,047,553), and a continuation-in-part of U.S. application Ser. No. 07/847,620 filed Mar. 4, 1992 now abandoned (a continuation of U.S. application Ser. No. 07/509,929, filed Apr. 16, 1990 now abandoned). This invention is directed to a method for the preparation of 3,4,6-trifluorophthalic acid. The product is a useful intermediate for the further preparation of 2,4,5-trifluorobenzoic acid which, in turn, is a useful chemical intermediate for the further preparation of such diverse products as liquid crystals and quinolone anti-bacterial agents.
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Related Publications (1)
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Number |
Date |
Country |
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847620 |
Mar 1992 |
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Divisions (1)
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Number |
Date |
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Parent |
315746 |
Feb 1989 |
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Continuations (1)
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Number |
Date |
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Parent |
509929 |
Apr 1990 |
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Continuation in Parts (1)
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Number |
Date |
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Parent |
653554 |
Feb 1991 |
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