# US 4,391,989 A · Oxydehydrogenation of isobutyric acid and its lower alkyl esters

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- Number: US 4,391,989 A
- Document ID: US4391989A
- Status: Granted
- Kind: A
- Application number: 06/319,489
- Filed: 1981-11-09
- Granted: 1983-07-05
- Earliest claimed: 1981-11-09
- Assignees: Ashland Oil, Inc.
- Inventors: Chelliah Daniel
- Web page: https://patentgrep.com/patent/US4391989A

## CPC

- B01J 27/19: Molybdenum
- C07C 51/377: by splitting-off hydrogen or functional groups; by hydrogenolysis of functional groups {(C07C51/36 - C07C51/373 take precedence)}
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

Isobutyric acid or a lower alkyl ester thereof is oxidatively dehydrogenated in the vapor phase to produce the corresponding .alpha.,B-olefinically unsaturated derivative by contact with a heterogeneous catalyst in the presence of molecular oxygen. The catalyst is composed of the calcined phosphates of chromium, molybdenum and tungsten.

## Claims

### Claim 1

In a process for the catalytic conversion of isobutyric acid or a lower alkyl ester thereof to the corresponding .alpha.,B-olefinically unsaturated derivative by oxydehydrogenation wherein a catalyst is contacted with a gaseous feed stream containing said acid or ester and molecular oxygen at a temperature between 300.degree. and 550.degree. C.; the improvement comprising using as catalyst a material having the gram-atom empirical formula Cr.sub.a P.sub.b W.sub.c Mo.sub.d O.sub.x wherein a is 0.01 to 1.0, b is 0.05 to 3.0, c is 0.01 to 3.0, d is 1 to 12.0, and x is determined by satisfying the sum of the unshared positive valences of the other elements shown in the formula.

### Claim 2 (depends on 1)

The process of claim 1 wherein isobutyric acid is converted to methacrylic acid.

### Claim 3 (depends on 2)

The process of claim 2 wherein the catalyst has the gram-atom empirical formula Cr.sub.0.3 P.sub.1.8 W.sub.0.02 Mo.sub.1.2 O.sub.x.