Process for preparing a cycloaliphatic diester

Patent metadata

Field	Value
Publication number	US-11655202-B2
Application number	US-201917268991-A
Country	US
Kind code	B2
Filing date	Aug 14, 2019
Priority date	Aug 17, 2018
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

The present invention relates to a method for producing a cycloaliphatic diester, to a method for producing a polyestercarbonate using the one cycloaliphatic diester, to the use of a cycloaliphatic diester for producing polyestercarbonates and also to a polyestercarbonate. The method according to the invention is here in particular characterized in that the cycloaliphatic diester is separated by means of distillation from the reaction mixture.

First claim

The invention claimed is:

1. A method for producing a cycloaliphatic diester of formula (Ia) or (Ib),

in which
A each independently is an aliphatic or aromatic radical and
n is a number between 0 and 3,
comprising the steps of
(i) reacting a mixture comprising at least one cycloaliphatic dicarboxylic acid and at least one aliphatic and/or aromatic carbonate, in the presence of a basic catalyst, to give a cycloaliphatic diester of formula (Ia) or (Ib) and
(ii) separating the cycloaliphatic diester of formula (Ia) or (Ib) from the mixture of method step (i) by means of distillation at a temperature of 180° C. to 280° C.

2. The method according to claim 1 , wherein the distillation in method step (ii) is conducted at pressures of 10 mbar or lower.

3. The method according to claim 1 , wherein, in method step (i), an aromatic carbonate of formula (2) is used

where R, R′ and R″ each independently can be the same or different and are hydrogen, optionally branched C1-C34-alkyl, C7-C34-alkylaryl or C6-C34-aryl, R can additionally also denote —COO—R′″, where R′″ is optionally branched C1-C34-alkyl, C7-C34-alkylaryl or C6-C34-aryl.

4. The method according to claim 3 , wherein, in method step (i), diphenyl carbonate is used as aromatic carbonate.

5. The method according to claim 1 , wherein method steps (i) and (ii) are conducted in the absence of an additional organic solvent.

6. The method according to claim 1 , wherein, in method step (i), at least one stabilizer selected from the group consisting of P-containing stabilizers and/or phenolic free-radical scavengers is added.

7. The method according to claim 1 , wherein the reaction of method step (i) is conducted at temperatures of 180 to 280° C.

8. The method according to claim 1 , wherein, during the reaction in method step (i), the volatile constituents which have a boiling point below the cycloaliphatic diester of formula (Ia) or (Ib) and below the aliphatic and/or aromatic carbonate are removed, optionally in steps, by means of distillation.

9. A method for producing a polyestercarbonate by means of melt transesterification, comprising the steps of:
(a) producing a cycloaliphatic diester of formula (Ia) or (Ib),

in which
A each independently is an aliphatic or aromatic radical and
n is a number between 0 and 3,
by:
(i) reacting a mixture comprising at least one cycloaliphatic dicarboxylic acid and at least one aliphatic and/or aromatic carbonate, in the presence of a basic catalyst, to give the cycloaliphatic diester of formula (Ia) or (Ib); and
(ii) separating the cycloaliphatic diester of formula (Ia) or (Ib) from the mixture of method step (i) by means of distillation at a temperature of 180° C. to 280° C.; and

(b) reacting the cycloaliphatic diester of formula (Ia) or (Ib) from method step (a), at least one dihydroxy compound and at least one diaryl carbonate in a melt transesterification process.

10. The method according to claim 9 , wherein method step (b) is performed immediately after method step (a).

11. The method according to claim 9 , wherein the dihydroxy compound in method step (b) is selected from the group consisting of cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, cyclohexane-1,2-dimethanol, cyclohexane-1,3-dimethanol, cyclohexane-1,4-dimethanol, tricyclodecanedimethanol, 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro [5.5] undecane, 2,2-bis(4-hydroxycyclohexyl)propane, tetrahydro-2,5-furandimethanol, bisphenol A, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4′-dihydroxybiphenyl (DOD), 4,4′-dihydroxybiphenyl ether (DOD ether), bisphenol B, bisphenol M, the bisphenols (I) to (III)

wherein the formula (I) to (III) R′ in each case is C1-C4-alkyl, aralkyl or aryl, butanediol, succinic acid, adipic acid, ethylene glycol, lactic acid, hexanediol and 1,4:3,6-dianhydrohexitols.

12. A method according to claim 9 , wherein as diaryl carbonate in method step (b) a compound of formula (2) is used

where R, R′ and R″ each independently can be the same or different and are hydrogen, optionally branched C1-C34-alkyl, C7-C34-alkylaryl or C6-C34-aryl, R can additionally also denote —COO—R′″, where R′″ is optionally branched C1-C34-alkyl, C7-C34-alkylaryl or C6-C34-aryl.

13. A method of producing a polyestercarbonate by means of melt transesterification comprising:
(a) producing a cycloaliphatic diester of formula (Ia) or (Ib),

in which
A each independently is an aliphatic or aromatic radical and
n is a number between 0 and 3,
by:
(i) reacting a mixture comprising at least one cycloaliphatic dicarboxylic acid and at least one aliphatic and/or aromatic carbonate, in the presence of a basic catalyst, to give the cycloaliphatic diester of formula (Ia) or (Ib); and
(ii) separating the cycloaliphatic diester of formula (Ia) or (Ib) from the mixture of method step (i) by means of distillation at a temperature of 180° C. to 280° C.; and

(b) reacting the cycloaliphatic diester of formula (Ia) or (Ib) with a bio-based dihydroxy compound and a diaryl carbonate.

14. The method according to claim 11 , wherein R′ in each case is methyl or phenyl.

15. The method according to claim 11 , wherein R′ in each case is methyl.

16. The method according to claim 11 , wherein the 1,4:3,6-dianhydrohexitol is selected from the group consisting of isomannide, isoidide and isosorbide.

17. The method according to claim 13 , wherein the bio-based dihydroxy compound comprises a 1,4:3,6-dianhydrohexitol.

18. The method according to claim 17 , wherein the 1,4:3,6-dianhydrohexitol is selected from the group consisting of isomannide, isoidide or isosorbide.

Assignees

• Covestro Intellectual Property Gmbh & Co Kg

Inventors

• Meyer Alexander
• Pfingst Thomas
• Hinzmann Dirk

Classifications

• C08G64/305

  and alcohols · CPC title

• C08G63/64

  Polyesters containing both carboxylic ester groups and carbonate groups · CPC title

• C07C69/75

  of acids with a six-membered ring · CPC title

• C07C67/10 Primary

  by reacting carboxylic acids or symmetrical anhydrides with ester groups or with a carbon-halogen bond (preparation from carboxylic acid halides C07C67/14) · CPC title

• C08G64/20

  General preparatory processes · CPC title