# US 9,517,986 B2 · Process for preparing 2,2′-biphenols using selenium dioxide

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- Number: US 9,517,986 B2
- Document ID: US9517986B2
- Status: Granted
- Kind: B2
- Application number: 14/719,900
- Filed: 2015-05-22
- Published: 2015-11-26
- Granted: 2016-12-13
- Earliest claimed: 2014-05-26
- Assignees: Evonik Degussa GmbH
- Applicants: Evonik Degussa GmbH
- Inventors: Katrin Marie Dyballa; Robert Franke; Dirk Fridag; Siegfried R. Waldvogel; Thomas Quell; Michael Mirion
- Web page: https://patentgrep.com/patent/US9517986B2

## CPC

- C07C 37/11: by reactions increasing the number of carbon atoms
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

A process for preparing a 2,2′-biphenol, proceeds by a) adding a first phenol to a reaction mixture, b) adding a second phenol to the reaction mixture, c) adding selenium dioxide to the reaction mixture, d) adding an acid having a pKa in the range from 0.0 to 5.0 to the reaction mixture, and e) heating the reaction mixture such that the first phenol and the second phenol are converted to said 2,2′-biphenol.

## Claims

### Claim 1

A process for preparing a 2,2′-biphenol, comprising:
a) adding a first phenol to a reaction mixture,
b) adding a second phenol to the reaction mixture,
c) adding selenium dioxide to the reaction mixture,
d) adding an acid having a pKa in the range from 0.0 to 5.0 to the reaction mixture, and
e) heating the reaction mixture such that the first phenol and the second phenol are converted to said 2,2′-biphenol.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the first phenol in process step a) is a compound of the general formula I:
wherein R1, R2, R3, R4, R5 are each independently selected from the group consisting of:
—H, —(C1-C12)-alkyl, —O—(C1-C12)-alkyl-, —(C6-C20)-aryl, —O—(C6-C20)-aryl, -halogen, and —OC═O—(C1-C12)-alkyl,
wherein two adjacent radicals are optionally joined to one another to form a condensed system,
wherein the alkyl and aryl groups mentioned are optionally substituted, and
wherein at least R1 or R5 is —H.

### Claim 3 (depends on 2)

The process according to claim 2, wherein R1, R2, R3, R4, R5 are each independently selected from the group consisting of:
—H—, —(C1-C12)-alkyl, —O—(C1-C12)-alkyl, —(C6-C20)-aryl, and —O—(C6-C20)-aryl,
wherein the alkyl and aryl groups mentioned are optionally substituted, and
wherein at least R′ or R5 is —H.

### Claim 4 (depends on 2)

The process according to claim 2, wherein R1, R3, R5 are each independently selected from the group consisting of:
—H, and —(C1-C12)-alkyl,
wherein the alkyl groups mentioned are optionally substituted, and
wherein at least R1 or R5 is —H.

### Claim 5 (depends on 1)

The process according to claim 1, wherein the second phenol in process step b) is a compound of the general formula II:
wherein R6, R7, R8, R9, R10 are each independently selected from the group consisting of:
—H, —(C1-C12)-alkyl-, —O—(C1-C12)-alkyl-, —(C6-C20)-aryl, —O—(C6-C20)-aryl, -halogen, and —OC═O—(C1-C12)-alkyl,
wherein two adjacent radicals are optionally joined to one another to form a condensed system,
wherein the alkyl and aryl groups mentioned are optionally substituted, and
wherein at least R6 or R10 is —H.

### Claim 6 (depends on 5)

The process according to claim 5, wherein R6, R7, R8, R9, R10 are each independently selected from the group consisting of:
—H—, —(C1-C12)-alkyl, —O—(C1-C12)-alkyl-, —(C6-C20)-aryl, and —O—(C6-C20)-aryl,
wherein the alkyl and aryl groups mentioned are optionally substituted, and
wherein at least R6 or R10 is —H.

### Claim 7 (depends on 5)

The process according to claim 5, wherein R6, R8, R10 are each independently selected from the group consisting of:
—H, and —(C1-C12)-alkyl,
wherein the alkyl groups mentioned are optionally substituted, and
wherein at least R6 or R10 is —H.

### Claim 8 (depends on 1)

The process according to claim 1, wherein the first phenol is the same as the second phenol.

### Claim 9 (depends on 1)

The process according to claim 1, wherein the selenium dioxide is added in process step c) in a molar ratio of from 0.25 to 1.2 based on a total sum of the first and second phenols.

### Claim 10 (depends on 1)

The process according to claim 1, wherein the acid in process step d) is selected from the group consisting of: acetic acid, formic acid, trifluoroacetic acid, propionic acid, and phosphoric acid.

### Claim 11 (depends on 1)

The process according to claim 1, wherein the acid is used as solvent in process step d).

### Claim 12 (depends on 1)

The process according to claim 1, wherein the reaction mixture is heated in process step e) to a temperature in the range from 50° C. to 110° C.

### Claim 13 (depends on 1)

The process according to claim 1, wherein the heating in process step e) is effected over a period in the range from 5 minutes to 24 hours.

### Claim 14 (depends on 1)

The process according to claim 1, wherein said bisphenol is selected from the group consisting of
3,3′,5,5′-tetramethylbiphenyl-2,2′-diol
3,3′-di-tert-butyl,5,5′-dimethylbiphenyl-2,2′-diol
3,3′,5,5′-tetra-tert-butylbiphenyl-2,2′-diol
3,3′-diisopropyl-5,5′,6,6′-tetramethyl-2,2′-biphenol
3,3′-di-tert-butyl-5,5′,6,6′-tetramethyl-2,2′-biphenol
and
3,3′,5,5′,6,6′-hexamethyl-2,2′-biphenol