Process for manufacturing polycarbonate from dianhydrohexitol Dialkylcarbonate

1. A process for manufacturing a polycarbonate with a glass transition temperature of greater than or equal to 50° C., comprising:

a step (1) of introducing, into a reactor, a monomer (A) of formula:

R1 and R2 being identical or different alkyl groups;

a step (2) of introducing, into the reactor, at least one cyclic diol or a mixture of diols (B) comprising at least 20 mol % of cyclic diols;

a step (3) of polycondensation by transesterification of the mixture comprising monomers (A) and (B); and

a step (4) of recovering the polycarbonate formed in step (3).

2. The process of claim 1 , wherein the alkyl groups R1 and R2 comprise from 1 to 10 carbon atoms.

3. The process of claim 1 , wherein (B) is a mixture of diols comprising, relative to the total number of diols, at least 50 mol % of a cyclic diol or of a mixture of cyclic diols.

4. The process of claim 1 , wherein the at least one cyclic diol(s) are selected from the group consisting of:

bisphenols such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane (bisphenol F), 1,1-bis(4-hydroxyphenyl)cyclohexane (bisphenol C), and 1,1-bis(4-hydroxyphenyl)ethane (bisphenol AD);

dianhydrohexitols such as isosorbide, isomannide and isoidide;

cyclohexanedimethanols such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol and 1,4-cyclohexanedimethanol;

tricyclodecanedimethanols;

pentacyclopentanedimethanols;

decalindimethanols such as 2,6-decalindimethanol, 1,5-decalindimethanol and 2,3-decalindimethanol;

norbornanedimethanols such as 2,3-norbornanedimethanol and 2,5-norbornanedimethanol;

adamantanedimethanols such as 1,3-adamantanedimethanol;

cyclohexanediols such as 1,2-cyclohexanediol, 1,3-cyclohexanediol and 1,4-cyclohexanediol;

tricyclodecanediols;

pentacyclopentadecanediols;

decalindiols;

norbornanediols; and

adamantanediols.

5. The process of claim 1 , wherein the at least one cyclic diol is isosorbide, isomannide, isoidide, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, or 1,4-cyclohexanedimethanol.

6. The process of claim 1 , further comprising a step (1′) of introducing, into the reactor, a monomer (C) of formula:

R3 and R4 being identical or different alkyl groups comprising from 1 to 10 carbon atoms.

7. The process of claim 1 , wherein the monomer (A) is an isosorbide dialkyl carbonate.

8. The process of claim 6 , wherein the molar amounts of monomers (A), (B) and (C) introduced are, relative to their total number:

from 1% to 60% of (A);

from 40% to 60% of (B); and

from 0% to 39% of (C),

the sum of (A), (B) and (C) being 100%.

9. The process of claim 6 , wherein the monomers (A), (B) and (C) constitute more than 90 mol % of the total amount of monomers introduced into the reactor.

10. The process of claim 1 , wherein step (3) takes place in the presence of a transesterification catalyst.

11. The process of claim 10 , wherein the catalyst comprises at least one of an alkali metal ion, an alkaline earth metal ion, a cyclic nitrogen compound, a quaternary ammonium ion, a quaternary phosphonium ion, a basic boron-based compound, or a basic phosphorous-based compound.

12. The process of claim 10 , wherein the molar amount of the catalyst is in a range of from 10 −7 % to 1%, relative to the amount of (A) and (C).

13. The process of claim 1 , wherein at least part of step (3) is performed at a temperature in a range of from 100° C. to 250° C.

14. The process as claimcd in of claim 1 , wherein at least part of step (3) is performed at a pressure in a range of from 30 kPa to 110 kPa.

15. The process of claim 1 , wherein the polycarbonate recovered in step (4) has a glass transition temperature in a range of from 90° C. to 180° C. and preferably from 110° C. to 170° C.

16. The process of claim 1 , wherein the alkyl groups R1 and R2 independently are methyl or ethyl groups.

17. The process of claim 1 , wherein the at least one cyclic diol is isosorbide.

18. The process of claim 6 , wherein the alkyl groups R3 and R4 independently are methyl or ethyl groups.

19. The process of claim 6 , wherein the molar amounts of monomers (A), (B) and (C) introduced are, relative to their total number:

from 39% to 59% of (A);

from 40% to 60% of (B); and

from 1% to 10% of (C),

the sum of (A), (B) and (C) being 100%.

20. The process of claim 10 , wherein the catalyst comprises cesium carbonate.