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US4038252A
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Phase boundary process for the preparation of aromatic polycarbonates using a chlorinated aromatic hydrocarbon as the polymer solvent
Assignee: Bayer AG
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Filing: 1975-03-04
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Granted: 1977-07-26
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Expires: 1995-03-04
Abstract
Abstract The present invention provides a process for the preparation of a polycarbonate by the phase boundary condensation method, by phosgenation of an aqueous alkali metal salt solution of one or more aromatic dihydroxy compounds, in which process an aromatic chlorinated hydrocarbon is used as the solvent and the synthesis of the polycarbonate is carried out in two stages, in the first stage of which the reaction of the alkali metal salt solution of the aromatic dihydroxy compound(s) with phosgene is carried out at an OH concentration of between 0.01 and 0.1% by weight of OH, relative to the aqueous phase, in the presence of 0.1 to 2.5 mol% of trialkylamine, relative to aromatic dihydroxy compound(s), and at a temperature higher than 70° C, with a dwell time of less than 5 minutes, while in the second stage the polycondensation is effected by adjusting the OH concentration to 0.20 to 0.50% by weight of OH, relative to the aqueous phase, optionally with further addition of trialkylamine, at a temperature higher than 80° C and with a dwell time of more than 1 minute.
Inventors
- 👤 Hugo Vernaleken
- 👤 Uwe Hucks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:06
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/20; C08G64/22; C08G64/24; C08G64/04; C08G64/06
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
183 words
A process for the preparation of a polycarbonate by the phase boundary condensation method, by phosgenation of an aqueous alkali metal salt solution of one or more aromatic dihydroxy compounds, in which the process an aromatic chlorinated hydrocarbon is used as the solvent and the synthesis of the polycarbonate is carried out in two stages, in the first stage of which the reaction of the alkali metal salt solution of the aromatic dihydroxy compoumd(s) with phosgene is carried out at an OH concentration of between 0.01 and 0.1% by weight of OH, relative to the aqueous phase, in the presence of 0.1 to 2.5 mol% of trialkylamine, relative to aromatic dihydroxy compound(s), and at a temperature higher than about 70° C., with a dwell time of less than about 5 minutes, while in a second stage the polycondensation is effected by adjusting the OH concentration to about 0.20 to 0.50% by weight of OH, relative to the aqueous phase, optionally with further addition of trialkylamine, at a temperature higher than about 80° C. with a dwell time of more than about 1 minute.
Claim 2
Dependent Claim
183 words
A process for the preparation of a polycarbonate by the phase boundary condensation method, by phosgenation of an aqueous alkali metal salt solution of one or more aromatic dihydroxy compounds, in which the process an aromatic chlorinated hydrocarbon is used as the solvent and the synthesis of the polycarbonate is carried out in two stages, in the first stage of which the reaction of the alkali metal salt solution of the aromatic dihydroxy compoumd(s) with phosgene is carried out at an OH concentration of between 0.01 and 0.1% by weight of OH, relative to the aqueous phase, in the presence of 0.1 to 2.5 mol% of trialkylamine, relative to aromatic dihydroxy compound(s), and at a temperature higher than about 70° C., with a dwell time of less than about 5 minutes, while in a second stage the polycondensation is effected by adjusting the OH concentration to about 0.20 to 0.50% by weight of OH, relative to the aqueous phase, optionally with further addition of trialkylamine, at a temperature higher than about 80° C. with a dwell time of more than about 1 minute.
Claim 3
Dependent Claim
14 words
A process according to claim 1, in which chlorobenzene is used as the solvent.
Claim 4
Dependent Claim
58 words
A process according to claim 1 in which the aromatic dihydroxy compounds are selected from dihydroxydiarylalkanes of the general formula ##STR4## in which X is C 1 -C 6 alkylene, C 2 -C 6 alkylidene, C 5 -C 15 cycloalkylene, C 5 -C 15 cycloalkylidene or ##STR5## R is hydrogen, chlorine, bromine or C 1 -C 4 alkyl.
Claim 5
Dependent Claim
38 words
A process according to claim 3, in which the aromatic dihydroxy compounds are selected from the group consisting of bisphenol A, tetrachlorobisphenol A, tetrabromobisphenol A, tetramethylbisphenol A, bisphenol Z, trinuclear bisphenol A and mixtures of these dihydroxy compounds.
Claim 6
Dependent Claim
44 words
A process according to claim 4 wherein chlorobenzene is used as the solvent, the trialkylamine is selected from the group consisting of triethylamine, triisobutylamine, tri-n-butylamine and mixtures of these catalysts and the dwell time in the first stage is less than about 3 minutes.
Claim 7
Dependent Claim
29 words
A process according to claim 5 wherein the alkali metal salt is selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide and mixtures of these hydroxides.
Claim 8
Dependent Claim
63 words
A process according to claim 6 wherein the phosgenation is carried out in a circulating reactor comprising a pipe loop with conveyor pump and inlet pipes for the reactants and an overflow for the reaction solution and the polycondensation reaction is carried out in a tube reactor comprising an alternating sequence of at least three mixing zones and at least three dwell zones.
Claim 9
Dependent Claim
30 words
A process according to claim 1 in which the alkali metal salt is selected from the group consisting of llithium hydroxide, sodium hydroxide, potassium hydroxide and mixtures of these hydroxides.
Claim 10
Dependent Claim
25 words
A process according to claim 1 in which the trialkylamine is selected from the group consisting of triethylamine, triisobutylamine, tri-n-butylamine and mixtures of these catalysts.
Claim 11
Dependent Claim
21 words
A process according to claim 1 in which the dwell time in the said first stage is less then 3 minutes.
Claim 12
Dependent Claim
22 words
A process according to claim 1 in which 1.05 to 1.20 mols of phosgene are employed per mol of aromatic dihydroxy compound.
Claim 13
Dependent Claim
64 words
A process according to claim 1 in which the phosgenation is carried out in a circulating reactor comprising a pipe loop with conveyor pump and inlet pipes for the reactants and an overflow for the reaction solution and the polycondensation reaction is carried out in a tube reactor comprising an alternating sequence of at least three mixing zones and at least three dwell zones.
Claim 14
Dependent Claim
9 words
A polycarbonate prepared by the process of claim 1.
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) | 1980-07-25 | 1981-01-24 | 1981-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-25 | 1985-01-24 | 1985-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-25 | 1989-01-24 | 1989-07-26 | $7700.00 | Window Closed / Lapsed |