US4954613A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalytic preparation of polycarbonate from dialkyl carbonate and bis phenol dicarboxylate
Assignee: BP Chemicals Ltd
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Filing: 1988-07-14
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Granted: 1990-09-04
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Expires: 2008-07-14
Abstract
Abstract This invention relates to an integrated process for producing polycarbonates by transesterification of a dialkyl carbonate with a bisphenol diester to form a carbonate oligomer and an alkyl ester followed by polymerization of the oligomer to a polycarbonate. The feature of the invention lies in the carbonylation of the alkyl ester by-product formed during the transesterification step to an ahydride which is used to esterify bisphenol to the diester.
Inventors
- 👤 Barry Hudson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:07
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/20; C08G64/30; Y; Y02; Y02P; Y02P20/00; Y02P20/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
111 words
An integrated process for producing polycarbonates, said process comprising: A. reacting in a transesterification reaction a dialkyl carbonate with a bisphenol dicarboxylate in contact with a catalyst to form a carbonate oligomer and an alkyl ester, and separating the alkyl ester from the oligomer; B. carbonylating the alkyl ester from step A with carbon monoxide in the presence of a carbonylation catalyst to form a product comprising an anhydride; C. reacting the product comprising the anhydride from step B with a bisphenol to form the bisphenol diester, and recycling the diester to step A; and D. heating the oligomer from step A in contact with a catalyst to form the polycarbonate.
Claim 2
Dependent Claim
111 words
An integrated process for producing polycarbonates, said process comprising: A. reacting in a transesterification reaction a dialkyl carbonate with a bisphenol dicarboxylate in contact with a catalyst to form a carbonate oligomer and an alkyl ester, and separating the alkyl ester from the oligomer; B. carbonylating the alkyl ester from step A with carbon monoxide in the presence of a carbonylation catalyst to form a product comprising an anhydride; C. reacting the product comprising the anhydride from step B with a bisphenol to form the bisphenol diester, and recycling the diester to step A; and D. heating the oligomer from step A in contact with a catalyst to form the polycarbonate.
Claim 3
Dependent Claim
19 words
A process according to claim 1 wherein the dialkyl carbonate in step A is dimethyl carbonate or diethyl carbonate.
Claim 4
Dependent Claim
46 words
A process according to claim 1 or 2 wherein the transesterification in step A is carried out in the presence of a tetraphenyl titanate catalyst at a temperature from 180°-300° C. or a pressure from 585-2315 Kilo pascals in an atmosphere inert under the reaction conditions.
Claim 5
Dependent Claim
33 words
A process according to claims 1 or 2 wherein the alkyl ester by-product from step A is methyl acetate and the anhydride formed by the carbonylation thereof in step B is acetic anhydride.
Claim 6
Dependent Claim
28 words
A process according to claims 1 or 2 wherein the anhydride formed in step B is reacted with the bisphenol at 140° C. to form the bisphenol diester.
Claim 7
Dependent Claim
42 words
A process according to claims 1 or 2 wherein the carbonate oligomer formed in step A is polymerised to form a high molecular weight polycarbonate in step D by heating the oligomer to a temperature above 250° C. in a mild vacuum.
References Cited (Backward Citations)
US4452968A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-09-03 | 1994-03-05 | 1994-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-03 | 1998-03-05 | 1998-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-03 | 2002-03-05 | 2002-09-04 | $7700.00 | Window Closed / Lapsed |