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US4005121A
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Process for the preparation of oligocarbonates with two catalysts
Assignee: Societe Nationale des Poudres et Explosifs
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Filing: 1975-12-04
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Granted: 1977-01-25
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Expires: 1995-12-04
Abstract
Abstract A process for the preparation of linear aliphatic polycarbonates having terminal hydroxyl groups is carried out in two stages:
Inventors
- 👤 Jean-Pierre G. Senet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:58
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/42; C08G18/44; C08G64/00; C08G64/02; C08G64/0208; C08G64/20; C08G64/30; C08G64/305
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
71 words
A process for the preparation of aliphatic polycarbonate-diols by transesterification between a diol and diethyl carbonate, which comprises the following two stages: I. transesterification carried out in the presence of a basic catalyst at a temperature below about 140° C, and Ii. after complete destruction of the basic catalyst, the transesterification is completed in the presence of an acid catalyst at a temperature of from about 200° to about 250° C.
Claim 2
Dependent Claim
71 words
A process for the preparation of aliphatic polycarbonate-diols by transesterification between a diol and diethyl carbonate, which comprises the following two stages: I. transesterification carried out in the presence of a basic catalyst at a temperature below about 140° C, and Ii. after complete destruction of the basic catalyst, the transesterification is completed in the presence of an acid catalyst at a temperature of from about 200° to about 250° C.
Claim 3
Dependent Claim
20 words
The process set forth in claim 1, wherein said basic catalyst is formed by adding sodium to the reaction mixture.
Claim 4
Dependent Claim
23 words
The process set forth in claim 2, wherein the amount of sodium used is from 0.1 to 0.5 g per mol of diol.
Claim 5
Dependent Claim
27 words
The process set forth in claim 1, wherein said basic catalyst is destroyed by adding an inorganic acid or an organic acid dichloride to the reaction mixture.
Claim 6
Dependent Claim
14 words
The process set forth in claim 4, wherein said inorganic acid is hydrochloric acid.
Claim 7
Dependent Claim
44 words
The process set forth in claim 1, wherein said basic catalyst is destroyed by dissolving the products obtained in the first stage in a water-immiscible solvent and washing the solution successively with an aqueous solution of an inorganic acid and then with pure water.
Claim 8
Dependent Claim
14 words
The process set forth in claim 6, wherein said inorganic acid is hydrochloric acid.
Claim 9
Dependent Claim
31 words
The process set forth in claim 1, wherein said acid catalyst is a monocarboxylic or dicarboxylic acid, the boiling point of which is higher than about 250° C under normal pressure.
Claim 10
Dependent Claim
27 words
The process set forth in claim 8, wherein the amount of acid catalyst used is less than 3 × 10 - 3 mol per mol of diol.
References Cited (Backward Citations)
US2915529A
Cited
US3549682A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-25 | 1980-07-26 | 1981-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-25 | 1984-07-26 | 1985-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-25 | 1988-07-26 | 1989-01-25 | $7700.00 | Window Closed / Lapsed |