US4022795A
Expired / Lapsed
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Method for dehalogenating aromatic compounds
Assignee: Imperial Chemical Industries Ltd
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Filing: 1975-08-19
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Granted: 1977-05-10
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Expires: 1995-08-19
Abstract
Abstract Dehalogenation of water-immiscible or sparingly soluble aromatic compounds containing chlorine or bromine by contacting with an aqueous solution of a formic acid salt in presence of a hydrogenation catalyst and a surface active agent.
Inventors
- 👤 Peter Bamfield
- 👤 Peter Michael Quan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:11
CPC Classifications
A; A62; A62D; A62D3/00; A62D3/30; A62D3/37; C; C07; C07C; C07C1/00; C07C1/26; C07C209/00; C07C209/30; C07C209/32; C07C209/36; C07C209/68; C07C209/74; C07C43/00; C07C43/02; C07C43/20; C07C43/205; C07C43/2055; C07C45/00; C07C45/61; C07C45/67; C07C45/68; C07C45/72; C07D; C07D213/00; C07D213/02; C07D213/04; C07D213/06; C07D213/22; A62D2101/00; A62D2101/20; A62D2101/22; C07C2521/00; C07C2521/18; C07C2523/00; C07C2523/38; C07C2523/40; C07C2523/44
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
95 words
A process for removing chlorine or bromine atoms without removing fluorine atoms from a compound selected from the group consisting of chlorobenzene, bromobenzene, 1-chloro-2-nitrobenzene, 5-chloro-2-aminobenzotrifluoride, 2,5-dichloronitrobenzene, 2-chloropyridine, 4-chloropyridine, 4-bromo-2,6-dimethylaniline, 1-chloronaphthalene, 1,2-dichlorobenzene, 4-bromobiphenyl and 2,6-difluoro-4-bromoaniline which comprises contacting said compound with an aqueous solution of a formic acid salt in the presence of a palladium-on-carbon hydrogenation catalyst and a surface active agent selected from the class consisting of water soluble salts of long chain carboxylic acids and sulphate esters, sodium diisopropylnaphthalene sulphonate, quaternary ammonium salts of long chain amines and polyalkenoxy derivatives of phenols and amines.
Claim 2
Dependent Claim
95 words
A process for removing chlorine or bromine atoms without removing fluorine atoms from a compound selected from the group consisting of chlorobenzene, bromobenzene, 1-chloro-2-nitrobenzene, 5-chloro-2-aminobenzotrifluoride, 2,5-dichloronitrobenzene, 2-chloropyridine, 4-chloropyridine, 4-bromo-2,6-dimethylaniline, 1-chloronaphthalene, 1,2-dichlorobenzene, 4-bromobiphenyl and 2,6-difluoro-4-bromoaniline which comprises contacting said compound with an aqueous solution of a formic acid salt in the presence of a palladium-on-carbon hydrogenation catalyst and a surface active agent selected from the class consisting of water soluble salts of long chain carboxylic acids and sulphate esters, sodium diisopropylnaphthalene sulphonate, quaternary ammonium salts of long chain amines and polyalkenoxy derivatives of phenols and amines.
Claim 3
Dependent Claim
12 words
Process according to claim 1 wherein the surface active agent is anionic.
Claim 4
Dependent Claim
14 words
Process according to claim 2 wherein the surface active agent is sodium diisopropylnaphthalene sulphonate.
Claim 5
Dependent Claim
30 words
Process according to claim 1, wherein the surface active agent is a phase transfer catalyst to promote the dehalogenation by transferring reactant from the aqueous phase to the non-aqueous phase.
Claim 6
Dependent Claim
89 words
Process according to claim 4 wherein the phase transfer catalyst is a quaternary ammonium salt of the formula ##STR2## wherein R 1 , R 2 , R 3 and R 4 , which may be the same or different, represent alkyl (C 1 to C 16 ), monocyclic aryl, benzyl, hydroxyalkyl (C 1 to C 16 ) or alkoxyalkyl (C 1 to C 16 ) radicals, and X represents one of the ions F, Cl, Br, OH, SO 4 , HSO 4 , SO 3 or HSO 3 .
Claim 7
Dependent Claim
89 words
Process according to claim 4 wherein the phase transfer catalyst is a quaternary phosphonium salt of the formula ##STR3## wherein R 1 , R 2 , R 3 and R 4 , which may be the same or different, represent alkyl (C 1 to C 16 ), monocyclic aryl, benzyl, hydroxyalkyl (C 1 to C 16 ) or alkoxyalkyl (C 1 to C 16 ) radicals, and X represents one of the ions F, Cl, Br, OH, SO 4 , HSO 4 , SO 3 or HSO 3 .
Claim 8
Dependent Claim
15 words
Process according to claim 1 wherein the formic acid salt is an alkali metal salt.
Claim 9
Dependent Claim
10 words
Process according to claim 1 wherein the catalyst is palladium-on-carbon.
Claim 10
Dependent Claim
14 words
Process according to claim 1 carried out at a temperature up to 150° C.
Claim 11
Dependent Claim
13 words
Process according to claim 9 carried out at a temperature of 75°-110° C.
Claim 12
Dependent Claim
13 words
Process according to claim 9 carried out at a temperature of 85°-102° C.
Claim 13
Dependent Claim
39 words
Process according to claim 1 wherein at least 3 mole equivalents of formic acid salt are used and the pH is near to neutrality, whereby to effect replacement of the said chlorine or bromine atom by a hydrogen atom.
Claim 14
Dependent Claim
42 words
Process according to claim 1 wherein from 1 to 3 mole equivalents of formic acid salt is added portionwise under strongly alkaline conditions to effect linkage of two aromatic nuclei at the positions formerly occupied by the said chlorine or bromine atoms.
References Cited (Backward Citations)
US1227144A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-09 | 1980-11-08 | 1981-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-09 | 1984-11-08 | 1985-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-09 | 1988-11-08 | 1989-05-10 | $7700.00 | Window Closed / Lapsed |