US3975441A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for recovering purified 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadiene-1-one
Assignee: Teijin Ltd
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Filing: 1974-04-29
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Granted: 1976-08-17
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Expires: 1994-04-29
Abstract
Abstract A process for recovering purified 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadiene-1-one by distilling crude 4-hydroxy-,2,4,6-trimethyl-2,5-cyclohexadien-1-one. Preferably, the distillation is performed at a temperature of 40° to 250°C. using crude 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one having a pH of 4 to 11.5. Thus, 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one of high purity and reduced coloration can be recovered at a high recovery ratio.
Inventors
- 👤 Yataro Ichikawa
- 👤 Yoshiyuki Yamanaka
- 👤 Nobuo Suzuki
- 👤 Hideki Tsuruta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:46
CPC Classifications
C; C07; C07C; C07C45/00; C07C45/78; C07C45/80; C07C45/27; C07C45/29; C07C45/32; C07C45/37; C07C45/39; C07C45/51; C07C45/516; C07C45/81; C07C45/82
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
114 words
A process for recovering purified 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one, which comprises distilling crude 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one having a pH of 4 to 11.5 at a temperature of 60° to 200°C. and under a pressure which is equal to or less than the vapor pressure of 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one at said distillation temperature and within the range of about 0.1 to about 180 mmHg absolute, said crude 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one being obtained by oxidizing 2,4,6-trimethyl phenol or by rearrangement of 1-hydroxyamino-2,4,6-trimethylbenzene, and said pH value being measured by a solution obtained by dissolving 4 parts by weight of crude 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one in an aqueous solution consisting of 10 parts by weight of methanol and 3 parts by weight of water, and recovering the purified 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one.
Claim 2
Dependent Claim
114 words
A process for recovering purified 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one, which comprises distilling crude 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one having a pH of 4 to 11.5 at a temperature of 60° to 200°C. and under a pressure which is equal to or less than the vapor pressure of 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one at said distillation temperature and within the range of about 0.1 to about 180 mmHg absolute, said crude 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one being obtained by oxidizing 2,4,6-trimethyl phenol or by rearrangement of 1-hydroxyamino-2,4,6-trimethylbenzene, and said pH value being measured by a solution obtained by dissolving 4 parts by weight of crude 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one in an aqueous solution consisting of 10 parts by weight of methanol and 3 parts by weight of water, and recovering the purified 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein the pH value is 5 to 11.
Claim 4
Dependent Claim
48 words
The process of recovering purified 1-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one according to claim 1, which comprises neutralizing a reaction mixture containing crude 1-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one or treating it with an extracting solvent to form crude 1-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one having a pH value of 4 to 11.5, distilling said crude 1-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one, and then recovering the purified 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one.
Claim 5
Dependent Claim
15 words
The process of claim 1 wherein said crude 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one is obtained by oxidizing 2,4,6-trimethyl phenol.
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) | 1979-08-17 | 1980-02-16 | 1980-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-17 | 1984-02-16 | 1984-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-17 | 1988-02-16 | 1988-08-17 | $7700.00 | Window Closed / Lapsed |