US4730083A
Expired / Lapsed
US
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Process for the preparation of 3,5-dialkyl-4-hydroxy benzoic acid
Assignee: Novartis Corp
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Filing: 1986-08-18
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Granted: 1988-03-08
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Expires: 2006-08-18
Abstract
Abstract An improved process for the preparation of 3,5-dialkyl-4-hydroxybenzoic acid comprising the reaction of 2,6-dialkylphenol and carbon dioxide in the presence of a mono- or polyalkylene glycol ether.
Inventors
- 👤 Stephen D. Pastor
- 👤 John d. Spivack
- 👤 Paul Odorisio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:10
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/15
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
71 words
A process for preparing 3,5-dialkyl-4-hydroxybenzoic acid which consists essentially of converting 2,6-dialkylphenol to the corresponding phenolate in the presence of an alkali or alkaline-earth metal hydroxide, hydride or amide and a mono- or polyalkylene glycol ether selected from the group consisting of ethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether, reacting the resulting phenolate with carbon dioxide at a temperature of from about 30°-60° C. and isolating the 3,5-dialkyl-4-hydroxybenzoic acid.
Claim 2
Dependent Claim
71 words
A process for preparing 3,5-dialkyl-4-hydroxybenzoic acid which consists essentially of converting 2,6-dialkylphenol to the corresponding phenolate in the presence of an alkali or alkaline-earth metal hydroxide, hydride or amide and a mono- or polyalkylene glycol ether selected from the group consisting of ethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether, reacting the resulting phenolate with carbon dioxide at a temperature of from about 30°-60° C. and isolating the 3,5-dialkyl-4-hydroxybenzoic acid.
Claim 3
Dependent Claim
17 words
The process of claim 1, wherein said alkyl groups independently contain from 1 to 30 carbon atoms.
Claim 4
Dependent Claim
20 words
The process of claim 2, wherein said alkyl groups independently are branched alkyl groups of 4 to 8 carbon atoms.
Claim 5
Dependent Claim
11 words
The process of claim 3, wherein said alkyl groups are tert-butyl.
Claim 6
Dependent Claim
26 words
The process of claim 1, wherein the reaction mixture is adjusted to a pH level of 1 to 2 prior to isolation of the benzoic acid.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-08 | 1991-09-07 | 1992-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-08 | 1995-09-07 | 1996-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-08 | 1999-09-07 | 2000-03-08 | $7700.00 | Window Closed / Lapsed |