Claims
- 1. A process for the selective polyhalogenation of an alkylbenzene having at least two alkyl chains so as to place a single halogen atom on each alkyl chain which comprises reacting an alkylbenzene with an N-halogenamine at a temperature of from -20.degree. C. to +40.degree. C. in the presence of a proton donor and of a catalyst constituted of a metal ion which is capable of existing in various oxidation states but which is in a lower oxidation state, the quantity of said catalyst varying from 1 to 50 mol % with respect to the alkyl side chains of the starting alkylbenzene, the molar ratio of said proton donor to said N-halogenamine being between 1.2 and 8.
- 2. A process as claimed in claim 1 wherein the proton donor is acetic acid, trifluoroacetic acid, mixtures thereof, or sulfuric acid, wherein said N-halogenamine derives from a primary or secondary amine with sufficient steric bulk and chain which has no C--H bonds in the delta position to the nitrogen atom, wherein the catalyst is constituted of a metal ion chosen from Fe.sup.2+, Cu.sup.+, Cr.sup.2+, Ti.sup.3+ and V.sup.2+, and wherein said alkylbenzene is selected from m-xylene, m-diisopropylbenzene, p-diisopropylbenzene, m-diethylbenzene, p-diethylbenzene, p-xylene, ethylbenzene and isopropylbenzene.
- 3. A process as defined in claim 2 wherein said alkylbenzene is m-xylene or p-xylene, the reaction is carried out at a temperature between -10.degree. C. and +10.degree. C., and a halogen atom is on each methyl group.
- 4. A process as defined in claim 2 wherein said proton donor is sulfuric acid at a concentration between 80 and 96%.
- 5. A process as defined in claim 2 wherein the molar ratio of said N-halogenamine is substantially the same as that of the alkyl side chains of the starting alkylbenzene.
- 6. A process as defined in claim 2 wherein said primary or secondary amine is diisopropylamine, diisobutylamine, diterbutylamine, dipropylamine, dicyclohexylamine, cyclohexylpropylamine, cyclohexylisopropylamine, cyclohexylmethylamine, cyclohexylethylamine, tetramethylpiperidine, piperidine, dibenzylamine, benzylethylamine or benzylpropylamine.
- 7. A process as defined in claim 2 wherein the reaction is carried out in the presence of an organic solvent chosen from esters, halogen or nitro derivatives of hydrocarbons, and nitriles.
Priority Claims (1)
Number |
Date |
Country |
Kind |
23440 A/80 |
Jul 1980 |
ITX |
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Parent Case Info
The present application is a continuation of application Ser. No. 279,260, filed July 1, 1981, now abandoned.
US Referenced Citations (3)
Foreign Referenced Citations (4)
Number |
Date |
Country |
45423 |
Aug 1980 |
EPX |
45425 |
Aug 1980 |
EPX |
55-79332 |
Jun 1980 |
JPX |
2080299 |
Feb 1982 |
GBX |
Non-Patent Literature Citations (3)
Entry |
Minisci et al., (R): Tetrahedron Letters, 699, (1966). |
Minisci et al., Tetrahedron Letter, 4663, 4667, (1965). |
Burton et al., Comprehensive Organic Chemistry, (1979), pp. 275-278, vol. 2. |
Continuations (1)
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Number |
Date |
Country |
Parent |
279260 |
Jul 1981 |
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