Claims
- 1. A process for producing a polycarbonate, which comprises transesterifying, in the presence of an antioxidant, (A) a dihydroxy compound or a precursor thereof and (B) a purified carbonic acid ester having, as an impurity, a chlorine content derived from chloroformate group of at most 30 ppm, which process comprises:
- (a) reacting said dihydroxy compound or a precursor thereof with said purified carbonic acid diester in the presence of said antioxidant, which is selected from the group consisting of tris(nonylphenyl)phosphite, triphenylphosphite, trimethylphosphite, 2-ethylhexyldiphenylphosphite, triethylphosphite, tricredylphosphite and triarylphosphite, at a temperature of from about 100.degree. C. to 330.degree. C. at a pressure of about 1 to 50 atmospheres to form an oligomer; and
- (b) further reacting said oligomer a temperature and under a reduced pressure of about 0.01 to 100 torr to form said polycarbonate of a desired molecular weight; and
- wherein said purified carbonic acid diester is purified prior to reaction by either:
- (i) being dissolved in a water-immiscible organic solvent, washed with an aqueous alkali solution having a pH of from 9 to 13, and then being washed with aqueous acid solution in an amount sufficient to effect neutralization, or
- (ii) being recrystallized from ethanol in the presence of a tertiary amine in the amount of 0.01 to 1.0 wt % and the resulting crystal being washed by a lower alcohol and water.
- 2. The process according to claim 1, wherein said carbonic acid diester (B) has a chlorine content derived from chloroformate group of less than 1 ppm.
- 3. The process according to claim 1, wherein the antioxidant is at least one member selected from the group consisting of tris (nonylphenyl)phosphite, trisphenylphosphite, 2 -ethylhexyldiphenylphosphite, trimethylphosphite, triethylphosphite, tricredylphosphite, and triarylphosphite.
- 4. The process according to claim 1, wherein the antioxidant is used in an amount of about 100 to 5000 ppm by weight based on the dihydroxy compound (A) or precursor thereof.
- 5. The process according to claim 1, wherein the dihydroxy compound has the formula: ##STR20## wherein R is a hydrogen atom, a halogen atom or an alkyl group having 1 to 8 carbon atoms, and when R is plural, each R is the same or different, and m is a number of 0 to 4; Z is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, or --S--, --SO--, --SO.sub.2 --, --O--, --CO--, or a direct bond or a linking group of the formula: ##STR21##
- 6. The process according to claim 1, wherein the carbonic acid diester is selected from the group consisting of diaryl carbonates, dialkyl carbonates and alkylaryl carbonates.
- 7. The process according to claim 6, wherein the chlorine content of the carbonic diester is at most 10 ppm.
- 8. The process according to claim 1, wherein the dihydroxy compound is selected from the group consisting of aromatic dihydroxy compounds and aliphatic dihydroxy compounds, and said presursor compound is selected from the group consisting of bisesters of aromatic dihydoxy comounds, bisesters of aliphatic dihydroxy compounds.
- 9. The process according to claim 6, wherein said diaryl carbonate is selected from the group consisting of diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis(diphenyl) carbonate and bisphenol A-bisphenol carbonate.
- 10. The process according to claim 6, wherein said dialkyl carbonate is selected from the group consisting of diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate and bisphenol A-bismethyl carbonate.
- 11. The process according to claim 6, wherein said alkylaryl carbonate is selected from the group consisting of methylphenyl carbonate, ethylphenyl carbonate, butylphenyl carbonate, cyclohexyl carbonate, diphenyl carbonate and bisphenol A-methylphenyl carbonate.
- 12. The process according to claim 1, which is further conducted in the presence of an inert medium for reducing viscosity of the reaction product.
- 13. The process according to claim 12, wherein said inert medium is diphenyl ether.
- 14. The process according to claim 1, which is further conducted in the presence of a transesterification catalyst.
- 15. The process according to claim 1, wherein said dihydroxy compound (A) or precursor thereof and said carbonic diester (B) are used in a ratio such that the amount of (B) is from 1 to 1.5 moles per mole of (A).
- 16. The process according to claim 1, which is conducted at a temperature in the range of from 180.degree. to 300.degree. C.
- 17. The process according to claim 1, wherein said pH in purification ii) is from 9 to 11.
- 18. The process according to claim 1, wherein said pH in purification ii) is from 10 to 13.
- 19. The process according to claim 1, wherein said tertiary amine is selected from the group consisting of pyridine or triethylamine.
Priority Claims (1)
Number |
Date |
Country |
Kind |
4-060079 |
Mar 1992 |
JPX |
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Parent Case Info
This application is a continuation-in-part (CIP) application of application Ser. No. 08/031,828, filed on Mar. 16, 1993.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
5187242 |
Sakashita et al. |
Feb 1993 |
|
5278279 |
Kanno et al. |
Jan 1994 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
31828 |
Mar 1993 |
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