Method for preparing a melt polycarbonate

• US 10,640,609 B2
• Filed: 12/20/2016
• Issued: 05/05/2020
• Est. Priority Date: 12/22/2015
• Status: Active Grant

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Vaporciyan, Garo Garbis, Yu, Kunquan
• Primary Examiner(s): Boykin, Terressa
• Application Number:
  US16/064,400
• Publication Number:
  US 20180371162A1
• Time in Patent Office: 1,232 Days
• Field of Search: 528196, 528198
• CPC Class Codes: C07C 68/06 from organic carbonates
• CPC Class Codes: C07C 69/96 Esters of carbonic or haloformic acids
• CPC Class Codes: C08G 2115/00 Oligomerisation
• CPC Class Codes: C08G 64/305 and alcohols
• CPC Class Codes: C08G 64/307 and phenols
• CPC Class Codes: C08L 69/00 Compositions of polycarbonates; Compositions of derivatives of polycarbonates

Abstract

A process for producing polycarbonate comprising: a) contacting a dialkyl carbonate with a dihydroxy compound in an oligomerization zone in the presence of an oligomerization catalyst under oligomerization conditions to form a first intermediate; and b) contacting the first intermediate with a diaryl carbonate in a polymerization zone in the presence of a polymerization catalyst under polymerization conditions to produce the polycarbonate wherein the molar ratio of dihydroxy compound to dialkyl carbonate in the oligomerization zone is at least 2:1.

Claims

1. A process for producing polycarbonate comprising:

a. contacting a dialkyl carbonate with a dihydroxy compound in an oligomerization zone in the presence of an oligomerization catalyst under oligomerization conditions to form a first intermediate; and

b. contacting the first intermediate with a diaryl carbonate in a polymerization zone in the presence of a polymerization catalyst under polymerization conditions to produce the polycarbonate

wherein the molar ratio of dihydroxy compound to dialkyl carbonate in the oligomerization zone is at least 2;

1, and wherein the dihydroxy compound is a dihydroxy aromatic compound.

2. The process of claim 1, further comprising passing the intermediate from step a) to an additional oligomerization zone to produce an oligomer with a longer chain length than the oligomer from step a).

3. The process claim 1, further comprising passing the polycarbonate from step b) to an additional polymerization zone to produce a polymer with a longer chain length than the polycarbonate from step b).

4. The process of claim 1, wherein the same catalyst is used for step a) and step b).

5. The process of claim 1, further comprising removing at least a portion of any unreacted dihydroxy compound from the first intermediate before reacting the first intermediate in step b).

6. The process of claim 1, wherein an alcohol is formed during the oligomerization.

7. The process of claim 6, further comprising removing at least a portion of the alcohol as an alcohol product stream.

8. The process of claim 1, wherein the dialkyl carbonate is selected from the group consisting of dimethylcarbonate, diethylcarbonate and mixtures thereof.

9. The process of claim 1, wherein the dihydroxy compound is bisphenol acetone.

10. The process of claim 1, wherein the diaryl carbonate is diphenylcarbonate.

11. The process of claim 1, wherein the first intermediate is a di-bisphenol acetone-carbonate compound.

12. The process of claim 1, wherein the molar ratio of dihydroxy compound to dialkyl carbonate in the oligomerization zone is at least 5:

1.

13. The process of claim 1, wherein the molar ratio of dihydroxy compound to dialkyl carbonate in the oligomerization zone is at least 10:

1.

14. The process of claim 1, wherein the molar ratio of dihydroxy compound to dialkyl carbonate in the oligomerization zone is in the range of from 2:

1 to 100;

1.

15. The process of claim 1, wherein the molar ratio of the first intermediate to the diaryl carbonate in the polymerization zone is from 1:

2 to 2;

1.

16. The process of claim 1, further comprising adding additives or other components to the polymerization zone.