# US 11,897,841 B2 · Isomerization method of cyclohexane dicarboxylic acid

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,897,841 B2
- Document ID: US11897841B2
- Status: Granted
- Kind: B2
- Application number: 15/734,621
- Filed: 2019-05-21
- Published: 2021-05-27
- Granted: 2024-02-13
- Earliest claimed: 2018-06-15
- Assignees: Hanwha Solutions Corporation
- Applicants: Hanwha Solutions Corporation
- Inventors: Jong Kwon Lee; Eun Jeong Kim; Sun Uk Lee; Nam Jin Jang
- Web page: https://patentgrep.com/patent/US11897841B2

## CPC

- C07C 51/353: by isomerisation; by change of size of the carbon skeleton
- B01J 21/063: {Titanium; Oxides or hydroxides thereof}
- B01J 21/066: {Zirconium or hafnium; Oxides or hydroxides thereof}
- C07B 2200/09: Geometrical isomers
- C07C 2601/14: The ring being saturated
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C07B: GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR (preparation of carboxylic acid esters by telomerisation C07C67/47; telomerisation C08F)

## Abstract

Provided is an isomerization method of cyclohexane dicarboxylic acid using zirconia or titania as an isomerization catalyst.

## Claims

### Claim 1

An isomerization method of cyclohexane dicarboxylic acid, comprising the step of isomerizing a cis isomer to a trans isomer by heat-treating a mixed solution which is prepared by mixing cyclohexane dicarboxylic acid comprising the cis isomer, water, and an isomerization catalyst,
wherein the mixed solution comprises the cyclohexane dicarboxylic acid in an amount of 0.5% by weight to 30% by weight with respect to the total weight of the mixed solution, and
the isomerization catalyst comprises one or more of oxide of a transition metal of Group 4, and is added in an amount such that a weight ratio of the isomerization catalyst to the cyclohexane dicarboxylic acid (a weight ratio of isomerization catalyst/cyclohexane dicarboxylic acid) of 0.1 or more.

### Claim 2 (depends on 1)

The isomerization method of cyclohexane dicarboxylic acid of claim 1, wherein the oxide of the transition metal of Group 4 comprises one or more selected from the group consisting of zirconia and titania.

### Claim 3 (depends on 1)

The isomerization method of cyclohexane dicarboxylic acid of claim 1, wherein the oxide of the transition metal of Group 4 is monoclinic zirconia.

### Claim 4 (depends on 1)

The isomerization method of cyclohexane dicarboxylic acid of claim 1, wherein the oxide of the transition metal of Group 4 is anatase titania.

### Claim 5 (depends on 1)

The isomerization method of cyclohexane dicarboxylic acid of claim 1, wherein the isomerization catalyst is added in an amount such that the weight ratio of the isomerization catalyst to cyclohexane dicarboxylic acid is 0.1 to 2.0.

### Claim 6 (depends on 1)

The isomerization method of cyclohexane dicarboxylic acid of claim 1, wherein the cyclohexane dicarboxylic acid is comprised in an amount of 0.8% by weight to 20% by weight with respect to the total weight of the mixed solution.

### Claim 7 (depends on 1)

The isomerization method of cyclohexane dicarboxylic acid of claim 1, wherein the heat treatment is performed at 220° C. to 280° C.