# US 10,370,491 B2 · Preparation of highly heat-resistant (co)polycarbonates by the transesterification method

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- Number: US 10,370,491 B2
- Document ID: US10370491B2
- Status: Granted
- Kind: B2
- Application number: 15/544,767
- Filed: 2016-01-20
- Published: 2017-12-28
- Granted: 2019-08-06
- Earliest claimed: 2015-01-20
- Assignees: Covestro Deutschland AG
- Applicants: Covestro Deutschland AG
- Inventors: Ivan Sluijs; Jan Heijl; Erik Sluyts; Frank Bruynseels
- Web page: https://patentgrep.com/patent/US10370491B2

## CPC

- C08G 64/14: containing a chain-terminating or -crosslinking agent
- C08G 64/307: {and phenols}
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

The present invention relates to a melt transesterification process for the production of (co)polycarbonates from diaryl carbonates and cycloalkylidene diphenols, which process comprises the addition of a monohydroxyaryl compound in an amount of 5.0 to 20.0 wt.-%, based on the total mass of the reaction mixture. The invention further relates to a (co)polycarbonate obtained by the process.

## Claims

### Claim 1

A process for preparing (co)polycarbonates by the melt transesterification method, the process comprising reacting at least one diaryl carbonate with a dihydroxyaryl compound of formula (1),
wherein
R1 is H or C1-C4-alkyl
R2 is C1-C4-Alkyl, and
n is 0, 1, 2 or 3;
wherein the process further comprises the addition of a monohydroxyaryl compound which corresponds to the monohydroxyaryl compound that is generated by the transesterification of the diaryl carbonate; and
wherein the monohydroxyaryl compound is added in an amount of 5.0 to 20.0 wt.-%, based on the total mass of the reaction mixture.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the diaryl carbonate is a compound of general formula (2)
wherein R, R′ and R″, independently of one another, are identical or different and represent hydrogen, linear or branched C1-C34-alkyl, C7-C34-alkylaryl or C6-C34-aryl.

### Claim 3 (depends on 1)

The process according to claim 1, wherein the diaryl carbonate is diphenyl carbonate.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the reaction mixture contains bisphenol A as a further dihydroxyaryl compound.

### Claim 5 (depends on 1)

The process according to claim 1, wherein the monohydroxyaryl compound is recovered from the product mixture.

### Claim 6 (depends on 5)

The process according to claim 5, wherein the recovered monohydroxyaryl compound is re-used in the process and/or used for producing diaryl carbonate.

### Claim 7 (depends on 5)

The process according to claim 5, wherein the recovered monohydroxyaryl compound is used for producing bisphenols.

### Claim 8 (depends on 1)

The process according to claim 1, wherein the diaryl carbonate is diphenyl carbonate and the monohydroxyaryl compound is phenol.

### Claim 9 (depends on 1)

The process according to claim 1, wherein R1 is H, R2 is methyl and n is 3.

### Claim 10 (depends on 1)

The process according to claim 1, wherein the diaryl compound is reacted with bisphenol A and bisphenol TMC.

### Claim 11 (depends on 1)

The process according to claim 1, wherein the monohydroxyaryl compound is added in an amount of 5.0 to 17.5 wt.-%, based on the total mass of the reaction mixture.

### Claim 12 (depends on 1)

The process according to claim 1, wherein the monohydroxyaryl compound is added in an amount of 7.0 to 15.0 wt.-%, based on the total mass of the reaction mixture.

### Claim 13 (depends on 1)

The process according to claim 1, wherein the monohydroxyaryl compound is added before or at the beginning of the transesterification reaction.

### Claim 14 (depends on 1)

A (co)polycarbonate obtained by the process according to claim 1.

### Claim 15 (depends on 1)

The process of claim 1, wherein the diaryl carbonate is reacted with the dihydroxyaryl compound of formula (1) and one or more further dihydroxyaryl compounds.