# US 4,394,522 A · Catalytic hydrogenation of di(4-aminophenyl)methane

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

- Number: US 4,394,522 A
- Document ID: US4394522A
- Status: Granted
- Kind: A
- Application number: 06/268,979
- Filed: 1981-06-01
- Granted: 1983-07-19
- Earliest claimed: 1981-06-01
- Assignees: Mobay Chemical Corporation
- Inventors: Gary F. Allen
- Web page: https://patentgrep.com/patent/US4394522A

## CPC

- C07C 209/72: by reduction of six-membered aromatic rings
- C07C 2601/14: The ring being saturated
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

The present invention relates to an improved process for the catalytic hydrogenation of di(4-amino-phenyl)methane to a liquid di(4-aminocyclohexyl)methane mixture containing from 15 to 40% by weight and preferably from 18.5 to 23.5% by weight, of the trans, trans isomer. The invention resides in the use of an unsupported ruthenium dioxide catalyst under specific process conditions. During the hydrogenation reaction, a pressure of at least 2500 psi and a temperature of from 150.degree. to 210.degree. C. must be maintained.

## Claims

### Claim 1

A process for the catalytic hydrogenation of di(4-aminophenyl)methane to a liquid di(4-aminocyclohexyl)methane containing from 15% to 40% by weight of the trans, trans isomer comprising hydrogenating di(4-aminophenyl)methane in the presence of an unsupported ruthenium dioxide catalyst under a hydrogen pressure of at least 2500 psi and at a temperature of from 150.degree. to 210.degree. C.

### Claim 2 (depends on 1)

The process of claim 1 wherein the trans, trans isomer content is from 18.5 to 23.5% by weight.

### Claim 3 (depends on 1)

The process of claim 1 wherein the hydrogenation is conducted in the presence of from 0 to 95% by weight of a solvent which is inert under the reaction conditions.

### Claim 4 (depends on 3)

The process of claim 3 wherein said solvent is n-butyl ether.

### Claim 5 (depends on 3)

The process of claim 3 wherein said solvent is used in an amount such that the concentration of the starting diamine is from about 5 to about 50% by weight.

### Claim 6 (depends on 1)

The process of claim 1 wherein the catalyst is present in an amount such that the amount of ruthenium metal present is at least 0.05% by weight based on the amount of starting diamine.

### Claim 7 (depends on 6)

The process of claim 6 wherein the amount of catalyst present is such that the amount of ruthenium metal is from about 0.1 to about 3% by weight.

### Claim 8 (depends on 1)

The process of claim 1 wherein the hydrogen pressure is from 2500 to 4000 psi.

### Claim 9 (depends on 1)

The process of claim 1 wherein the hydrogen pressure is from 2500 to 8000 psi.

### Claim 10 (depends on 1)

The process of claim 1 wherein the reaction is conducted for a period of from about 30 minutes to about 90 minutes.