Patent US4127561A successfully refreshed from Google Patents.
US4127561A
Expired / Lapsed
US
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Polycarbonates and a process for their preparation
Assignee: Bayer AG
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Filing: 1978-02-27
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Granted: 1978-11-28
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Expires: 1998-02-27
Abstract
Abstract The present invention provides thermoplastic aromatic polycarbonates and a process for their production according to the phase boundary polycondensation process, characterized in that tertiary amines are employed as catalysts and are distilled beforehand over about 0.3-10% by weight, relative to the weight of the tertiary amine, of reducing agents and/or acid anhydrides with the exclusion of atmospheric oxygen.
Inventors
- 👤 Wolfgang Alewelt
- 👤 Gunter Jacobs
- 👤 Dieter Margotte
- 👤 Erich Lux
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:47
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/20; C08G64/26; C08G64/28; C08G64/04; C08G64/06; C08G64/14; C08G64/22; C08G64/24
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
43 words
In a process for the preparation of thermoplastic, aromatic polycarbonates according to the phase boundary polycondensation reaction using tertiary amines as catalysts, the improvement wherein the tertiary amines are distilled beforehand over reducing agents and/or acid anhydrides with the exclusion of atmospheric oxygen.
Claim 2
Dependent Claim
43 words
In a process for the preparation of thermoplastic, aromatic polycarbonates according to the phase boundary polycondensation reaction using tertiary amines as catalysts, the improvement wherein the tertiary amines are distilled beforehand over reducing agents and/or acid anhydrides with the exclusion of atmospheric oxygen.
Claim 3
Dependent Claim
23 words
The process of claim 1, wherein the tertiary amines are selected from the group consisting of triethylamine, tri-butyl-amine, N,N-dimethyl-cyclohexylamine, N,N-diethyl-cyclohexylamine, N,N-dimethylaniline, and N,N-diethylaniline.
Claim 4
Dependent Claim
13 words
The process of claim 2, wherein the tertiary amines are triethylamine or tri-butyl-amine.
Claim 5
Dependent Claim
27 words
The process of claim 1, wherein the acid anhydrides are selected from the group consisting of acetic anhydride, propionic anhydride, benzoic anhydride, phthalic anhydride and pyromellitic anhydride.
Claim 6
Dependent Claim
32 words
The process of claim 1 wherein the reducing agent is selected from the group consisting of complex metal hydrides, alkali metal sulphites, alkali earth metal sulphites, bisulphites, thiosulphates, and sulphides and hydrogen.
Claim 7
Dependent Claim
31 words
The process according to claim 1, wherein the reducing agents and/or acid anhydrides are employed in amounts between about 0.3 and 10% by weight, relative to the weight of tertiary amine.
Claim 8
Dependent Claim
11 words
The process according to claim 1, wherein phthalic anhydride is employed.
Claim 9
Dependent Claim
19 words
The process according to claim 1, wherein the reducing agent is a mixture of sodium borohydride and Raney nickel.
Claim 10
Dependent Claim
18 words
The process according to claim 1, wherein the tertiary amine is dried to remove water therefrom before distillation.
Claim 11
Dependent Claim
31 words
The process of claim 1, wherein complex metal hydrides selected from the group consisting of sodium borohydride and lithium borohydride, optionally in combination with Raney nickel are used as reducing agents.
Claim 12
Dependent Claim
27 words
The process of claim 1, wherein acid anhydrides selected from the group consisting of acid anhydrides of carboxylic acids and acid anhydrides of inorganic acids are used.
Claim 13
Dependent Claim
20 words
The process of claim 11, wherein the acid anhydrides of carboxylic acids having 4 to 14 carbon atoms are used.
Claim 14
Dependent Claim
18 words
The process of claim 11, wherein P 2 O 5 is the acid anhydride of an inorganic acid.
Claim 15
Dependent Claim
12 words
The process of claim 1, wherein inorganic salt reducing agents are used.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-11-27 | 1982-05-29 | 1982-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-27 | 1986-05-29 | 1986-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-27 | 1990-05-29 | 1990-11-28 | $7700.00 | Window Closed / Lapsed |