# US 5,352,839 A · Isophorone process

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- Number: US 5,352,839 A
- Document ID: US5352839A
- Status: Granted
- Kind: A
- Application number: 08/118,341
- Filed: 1993-09-09
- Granted: 1994-10-04
- Earliest claimed: 1993-09-09
- Assignees: Aristech Chemical Corporation
- Inventors: Michael C. Grebinoski; Donald Glassman; Carole L. Elias; Alain A. Schutz
- Web page: https://patentgrep.com/patent/US5352839A

## CPC

- C07C 45/74: combined with dehydration
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

Isophorone is made by the aldol condensation of acetone followed by separate steps to remove acetone, mesityloxide, and beta isophorone. Variations include recycling of mesityloxide and/or beta isophorone.

## Claims

### Claim 1

Method of making isophorone comprising conducting an aldol condensation of acetone in the vapor phase in the presence of an aldol condensation catalyst at a temperature between about 225.degree. C. to about 325.degree. C. to obtain a reaction product in which at least about 10% of the acetone is converted, removing unreacted acetone in an acetone removal zone, removing free water from the reaction product, removing mesityloxide and water in a mesityloxide removal zone, thereafter removing beta isophorone and mesitylene from said reaction product in a beta isophorone and mesitylene removal zone, and purifying the remaining reaction product to obtain an end product of at least 99% purity.

### Claim 2 (depends on 1)

Method of claim 1 wherein the acetone removal zone comprises a distillation column .

### Claim 3 (depends on 1)

Method of claim 1 wherein the removal of free water is conducted in a decanter.

### Claim 4 (depends on 1)

Method of claim 1 wherein the mesityloxide removal zone comprises a distillation column.

### Claim 5 (depends on 1)

Method of claim 1 wherein the beta isophorone and mesitylene removal zone comprises a distillation column, beta isophorone is removed at an intermediate level thereof, and the mesitylene is purged.

### Claim 6 (depends on 1)

Method of claim 1 wherein the purifying is conducted by distillation.

### Claim 7 (depends on 1)

Method of claim 1 wherein the catalyst is a synthetic anionic clay of the formula (Mg.sub.1-x Al.sub.x)(OH).sub.2.xA where x is a number from 0.1 to 0.5, A is a univalent organic anion of the formula RCOO.sup.--, where R is CnH.sub.2n+ and n is 0 to 4.

### Claim 8 (depends on 2)

Method of claim 2 wherein the distillation column in the acetone removal zone is operated at a pressure of 300 mmHg to 20 psig.

### Claim 9 (depends on 4)

Method of claim 4 wherein the distillation column in the mesityloxide removal zone is operated at a pressure of 100 mmHg to 20 psig.

### Claim 10 (depends on 5)

Method of claim 5 wherein the distillation column in the beta isophorone and mesitylene removal zone is operated at a pressure of 20 mmHg to 5 psig.

### Claim 11 (depends on 1)

Method of claim 1 wherein the purification step is conducted in a distillation column operated at a pressure of 10 mmHg to 5 psig.

### Claim 12 (depends on 1)

Method of claim 1 wherein the acetone removed in the first treatment zone is recycled to the reactor.

### Claim 13 (depends on 1)

Method of claim 1 wherein the mesityloxide removed in the mesityloxide removal zone is recycled to the reactor.

### Claim 14 (depends on 1)

Method of claim 1 wherein the beta isophorone removed in the beta isophorone and mesitylene removal zone is recycled to the reactor.

### Claim 15 (depends on 1)

Method of claim 1 wherein about 4% to about 20% of the initial reaction product comprises alpha isophorone.

### Claim 16 (depends on 8)

Method of claim 8 wherein the pressure is 650 mmHg to 850 mmHg.

### Claim 17 (depends on 9)

Method of claim 9 wherein the pressure is 400 mmHg to 600 mmHg.

### Claim 18 (depends on 10)

Method of claim 10 wherein the pressure is 100 mmHg to 300 mmHg.

### Claim 19 (depends on 11)

Method of claim 11 wherein the pressure is 50 mmHg to 100 mmHg.