US3679710A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of isomerizing 4-cyclo-hexene-1,2-dicarboxylic acid anhydrides
Assignee: Reichhold Chemicals Inc
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Filing: 1970-05-18
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Granted: 1972-07-25
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Expires: 1990-05-18
Abstract
Abstract A method for preparing liquid mixtures of isomers of both the cis and trans forms of 4-cyclohexene-1,2-dicarboxylic anhydride and its nuclear alkyl derivatives and resulting product. These liquid mixtures are prepared by isomerizing the anhydride with a catalyst consisting of boric acid and oxalic acid, at temperatures between about 65* C. and about 185* C. This procedure permits the use of mild reaction conditions and yields a product having improved color, less by-products and low viscosity as compared to products prepared by heretofore known methods.
Inventors
- 👤 Wolfgang C Forster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:14
CPC Classifications
C; C07; C07C; C07C61/00; C07C61/16; C07C61/22; C07C61/24
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
43 words
A process according to claim 1, wherein the amount of catalyst ranges from about 0.01 percent to about 2 percent of (A) and from about 0.01 percent to about 2 percent of (B), the percentages being based on the weight of the anhydride.
References Cited (Backward Citations)
US2959599A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |