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Patent US4452968A successfully refreshed from Google Patents.
US4452968A
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US
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Synthesis of polycarbonate from dialkyl carbonate and bisphenol diester
Assignee: General Electric Co
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Filing: 1983-03-25
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Granted: 1984-06-05
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Expires: 2003-03-25
Abstract
Abstract Polycarbonates are formed by the interaction of a bisphenol diester, carbon monoxide and oxygen. The initial polycarbonate product is an oligomer which, upon heat treatment, polymerizes to a high molecular weight polycarbonate. The products produced according to the present invention are chainstopped prior to heat treatment, making them less thermally and oxidatively sensitive.
Inventors
- 👤 Donald A. Bolon
- 👤 John E. Hallgren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:38
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/20; C08G64/36; C08G64/04; C08G64/06; C08G64/14; C08G64/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
203 words
A process for producing a polycarbonate resin of the formula ##STR4## where Ac is an acyloxy radical, BP is the residue obtained by removing the hydroxy groups from a bisphenol, R is an alkyl radical, m is a number greater than 10, x is a number from 0.2 to 1, y is a number from 1.0 to 1.8, and the sum of x and y is 2, comprising the steps of: A. reacting an alkanol of the formula ROH with carbon monoxide and oxygen to produce a dialkyl carbonate and water, and removing said water; B. reacting said dialkyl carbonate with a bisphenol diester of the formula BPAc 2 in contact with a catalyst to produce an oligomer having the formula ##STR5## where n is a number from 1 to 4, and an alkyl ester of the formula RAc; C. separating said alkyl ester and heating it to produce said alkanol and a ketene, and recycling said alkanol to step A; D. separating said ketene, reacting said ketene with said bisphenol to produce said bisphenol diester, and recycling said bisphenol diester to step B; and E. heating the oligomer produced in step B in contact with said catalyst to produce said polycarbonate resin.
Claim 2
Dependent Claim
203 words
A process for producing a polycarbonate resin of the formula ##STR4## where Ac is an acyloxy radical, BP is the residue obtained by removing the hydroxy groups from a bisphenol, R is an alkyl radical, m is a number greater than 10, x is a number from 0.2 to 1, y is a number from 1.0 to 1.8, and the sum of x and y is 2, comprising the steps of: A. reacting an alkanol of the formula ROH with carbon monoxide and oxygen to produce a dialkyl carbonate and water, and removing said water; B. reacting said dialkyl carbonate with a bisphenol diester of the formula BPAc 2 in contact with a catalyst to produce an oligomer having the formula ##STR5## where n is a number from 1 to 4, and an alkyl ester of the formula RAc; C. separating said alkyl ester and heating it to produce said alkanol and a ketene, and recycling said alkanol to step A; D. separating said ketene, reacting said ketene with said bisphenol to produce said bisphenol diester, and recycling said bisphenol diester to step B; and E. heating the oligomer produced in step B in contact with said catalyst to produce said polycarbonate resin.
Claim 3
Dependent Claim
56 words
The process of claim 1 wherein Ac is selected from the class consisting of acetoxy and propionoxy; BP is the residue obtained by removing the hydroxy groups from a bisphenol selected from the class consisting of bisphenol-A, tetramethyl bisphenol-A, biphenol and tetrabromo bisphenol-A; and R is selected from the class consisting of methyl, ethyl and propyl.
Claim 4
Dependent Claim
25 words
The process of claim 2 wherein Ac is acetoxy, BP is the residue obtained by removing the hydroxy groups from bisphenol-A, and R is methyl.
Claim 5
Dependent Claim
38 words
The process of claim 2 wherein step B is conducted in contact with 0.001 to 0.005% by weight, calculated as TiO 2 and based on bisphenol-A, of a titanate catalyst at a temperature from 180° to 300° C.
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) | 1987-06-05 | 1987-12-05 | 1988-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-05 | 1991-12-05 | 1992-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-05 | 1995-12-05 | 1996-06-05 | $7700.00 | Window Closed / Lapsed |