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US4772729A
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Hydrogenation of citric acid and substituted citric acids to 3-substituted tetrahydrofuran, 3- and 4-substituted butyrolactones and mixtures thereof
Assignee: Invista North America LLC
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Filing: 1987-01-23
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Granted: 1988-09-20
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Expires: 2007-01-23
Abstract
Abstract A process is disclosed for preparing 3-substituted tetrahydrofuran, 3- and 4-substituted butyrolactones and mixtures thereof comprising hydrogenating a hydrogenatable precursor in the presence of an aqueous reaction medium and a catalyst comprising palladium and rhenium and at least one support selected from the group consisting of titanium oxide, zirconium oxide, and carbon.
Inventors
- 👤 Velliyur N. M. Rao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:02
CPC Classifications
C; C07; C07D; C07D315/00; C07D307/00; C07D307/02; C07D307/04; C07D307/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
64 words
A process for preparing 3-substituted tetrahydrofuran, 3- and 4-substituted butyrolactones and mixtures thereof comprising contacting a hydrogenatable precursor selected from the group consisting of citric acid and substituted citric acid with a catalyst comprising palladium and rhenium and at least one support selected from the group consisting of titanium oxide, zirconium oxide, and carbon in the presence of an aqueous reaction medium and hydrogen.
Claim 2
Dependent Claim
64 words
A process for preparing 3-substituted tetrahydrofuran, 3- and 4-substituted butyrolactones and mixtures thereof comprising contacting a hydrogenatable precursor selected from the group consisting of citric acid and substituted citric acid with a catalyst comprising palladium and rhenium and at least one support selected from the group consisting of titanium oxide, zirconium oxide, and carbon in the presence of an aqueous reaction medium and hydrogen.
Claim 3
Dependent Claim
13 words
A process according to claim 1, wherein the hydrogenatable precursor is citric acid.
Claim 4
Dependent Claim
14 words
A process according to claim 1, wherein the support is titanium oxide or carbon.
Claim 5
Dependent Claim
29 words
A process according to claim 3, wherein the catalyst comprises from about 1 to about 19 weight percent palladium and from about 4 to about 76 weight percent rhenium.
Claim 6
Dependent Claim
23 words
A process according to claim 4, wherein the process is conducted at a temperature of from about 100° C. to about 300° C.
Claim 7
Dependent Claim
23 words
A process according to claim 5, wherein the process is conducted at a temperature of from about 150° C. to about 250° C.
Claim 8
Dependent Claim
23 words
A process according to claim 6, wherein the process is conducted at a pressure of from about 3.5 MPa to about 27.6 MPa.
Claim 9
Dependent Claim
23 words
A process according to claim 7, wherein the process is conducted at a pressure of from about 3.5 MPa to about 17.3 MPa.
Claim 10
Dependent Claim
13 words
A process according to claim 8, wherein the aqueous reaction medium is water.
References Cited (Backward Citations)
GB1149784A
Cited
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Cited
US4096156A
Cited
US4105674A
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US4550185A
Cited
US4609636A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-20 | 1992-03-21 | 1992-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-20 | 1996-03-21 | 1996-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-20 | 2000-03-21 | 2000-09-20 | $7700.00 | Window Closed / Lapsed |