US4474994A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of vanillin
Assignee: Rhone Poulenc Surfactants and Specialties LP
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Filing: 1982-09-13
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Granted: 1984-10-02
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Expires: 2002-09-13
Abstract
Abstract Crude vanillin is purified by supercritical extraction of impurities. The process is especially useful in purifying crude vanillin obtained from paper mill waste liquors. Preferred supercritical extraction fluid is CO2.
Inventors
- 👤 Earle C. Makin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:34
CPC Classifications
B; B01; B01D; B01D11/00; B01D11/02; B01D11/0203; C; C07; C07C; C07C45/00; C07C45/78; C07C45/80; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/54
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
106 words
A process for purification of crude vanillin, comprising: a. contacting crude vanillin obtained from lignin, lignosulfonates, or sulfite cooking liquor comprising at least 50 weight percent vanillin with a supercritical extraction fluid which preferentially dissolves the impurities in the crude vanillin, selected from the group consisting of CO 2 , ethane, and ethylene, at a temperature in excess of the critical temperature of the extraction fluid and at a pressure of 25 to 500 atmospheres; b. extracting from the crude vanillin at least some of the impurities; and c. separating the supercritical fluid containing impurities from the crude vanillin to produce vanillin product with increased purity.
Claim 2
Dependent Claim
106 words
A process for purification of crude vanillin, comprising: a. contacting crude vanillin obtained from lignin, lignosulfonates, or sulfite cooking liquor comprising at least 50 weight percent vanillin with a supercritical extraction fluid which preferentially dissolves the impurities in the crude vanillin, selected from the group consisting of CO 2 , ethane, and ethylene, at a temperature in excess of the critical temperature of the extraction fluid and at a pressure of 25 to 500 atmospheres; b. extracting from the crude vanillin at least some of the impurities; and c. separating the supercritical fluid containing impurities from the crude vanillin to produce vanillin product with increased purity.
Claim 3
Dependent Claim
13 words
Process of claim 1 wherein the crude vanillin comprises 70 weight percent vanillin.
Claim 4
Dependent Claim
25 words
Process of claim 1 wherein the impurities in the crude vanillin include one or more of acetovanillone, p-hydroxybenzaldehyde, 5-formyl vanillin, syringic aldehyde, and mixtures thereof.
Claim 5
Dependent Claim
13 words
Process of claim 1 wherein the supercritical extraction fluid is CO 2 .
Claim 6
Dependent Claim
26 words
Process of claim 4 wherein the supercritical extraction conditions include a temperature of 31.6 to 90 C. and a pressure of 25 to 500 atmospheres, absolute.
Claim 7
Dependent Claim
25 words
Process of claim 4 wherein supercritical extraction conditions include a temperature of 35 to 50 C. and a pressure of 40 to 100 atmospheres, absolute.
Claim 8
Dependent Claim
28 words
Process of claim 4 wherein the volume ratio of CO 2 to crude vanillin is 1:1 to 100:1, on a volumetric basis as measured at supercritical extraction conditions.
Claim 9
Dependent Claim
18 words
Process of claim 4 wherein the weight ratio of CO 2 to crude vanillin is 10:1 to 30:1.
Claim 10
Dependent Claim
21 words
Process of claim 1 wherein the residence time of crude vanillin within the supercritical extraction zone is 1 to 1,000 minutes.
Claim 11
Dependent Claim
58 words
A process for purifying crude vanillin, obtained from spent sulfite liquors containing 70 to 98 weight percent vanillin, comprising contacting said crude vanillin at a temperature of 35 to 50 C., and pressure of 40 to 100 atmospheres with CO 2 , whereby the CO 2 extracts impurities from the crude vanillin, to produce a purified vanillin product.
Claim 12
Dependent Claim
58 words
A process for purifying crude vanillin, obtained from spent sulfite liquors containing 70 to 98 weight percent vanillin, comprising contacting said crude vanillin at a temperature of 35 to 50 C., and pressure of 40 to 100 atmospheres with CO 2 , whereby the CO 2 extracts impurities from the crude vanillin, to produce a purified vanillin product.
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) | 1987-10-02 | 1988-04-02 | 1988-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-02 | 1992-04-02 | 1992-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-02 | 1996-04-02 | 1996-10-02 | $7700.00 | Window Closed / Lapsed |