# US RE31,260 E · Process for the preparation of an acetonitrile derivative

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- Number: US RE31,260 E
- Document ID: USRE31260E
- Status: Granted
- Kind: E
- Application number: 06/163,702
- Filed: 1980-06-27
- Granted: 1983-05-31
- Earliest claimed: 1977-03-15
- Assignees: Labaz
- Inventors: Michel Chignac; Claude Grain; Charles Pigerol
- Web page: https://patentgrep.com/patent/USRE31260E

## Abstract

Process for the preparation of di-n-propyl acetonitrile of the formula: ##STR1## whereby, in a single step, sodium n-propylate in n-propanol medium is added to a reaction medium which is formed of a cyanacetate of general formula: ##STR2## in which R represents an alkyl radical having from 1 to 4 carbon atoms, and n-propyl bromide or iodide, the alkylation reaction taking place under reflux, the crude ester obtained is saponified with a 10 to 20% solution of sodium hydroxide or potassium hydroxide, the resulting salt is acidified with a strong acid, to give crude di-n-propyl cyanacetic acid, which is decarboxylated by heating at a temperature between 140.degree. C. and 190.degree. C., so as to obtain the di-n-propyl acetonitrile.

## Claims

### Claim 1

Process for the preparation of di-n-propylacetonitrile of the formula: ##STR5## whereby, (a) sodium n-propylate in n-propanol medium is added to a reaction medium which is formed of a cyanacetate of general formula: ##STR6## in which R represents an alkyl radical having from 1 to 4 carbon atoms, and n-propyl bromide or iodide, the alkylation reaction taking place under reflux at atmospheric pressure, (b) the crude ester obtained is saponified at a temperature between 30.degree. and 70.degree. C. with a 10 to 20% by weight solution of sodium hydroxide or potassium hydroxide in the proportion of 1.25 to 2 mols of sodium or potassium hydroxide per mol of crude ester, the resulting salt is acidified with a strong acid at a temperature not exceeding 40.degree. C., to give crude di-n-propyl cyanacetic acid, (c) which is decarboxylated solely by heating, in the absence of any supplementary agent, at a temperature between 140.degree. C. and 190.degree. C., so as to obtain the di-n-propylacetonitrile.

### Claim 2 (depends on 1)

Process according to claim 1, wherein the cyanacetate is methyl cyanacetate or ethyl cyanacetate.

### Claim 3 (depends on 1)

Process according to claim 1, whereby the addition of sodium n-propylate is carried out when the temperature of the reaction medium is at 45.degree. C. to 55.degree. C.

### Claim 4 (depends on 1)

Process according to claim 1, whereby the saponification is effected in the presence of a quaternary ammonium salt.

### Claim 5 (depends on 4)

Process according to claim 4, wherein the quaternary ammonium salt is trimethyl cetylammonium bromide.

### Claim 6 (depends on 4)

Process according to claim 4, whereby the saponification is carried out in the presence of 0.005 to 0.1 mol of quaternary ammonium salt mol of crude ester.

### Claim 7 (depends on 1)

Process according to claim 1, whereby the acidification takes place by means of 36% hydrochloric acid at a temperature which does not exceed 40.degree. C.

### Claim 8 (depends on 1)

Process according to claim 1, whereby the decarboxylation takes place at a temperature which is between 175.degree. and 190.degree. C.

### Claim 9 (depends on 1)

Process according to claim 1, whereby the decarboxylation operation is carried out by continuously transferring the di-n-propyl cyanacetic acid into the decarboxylation medium and by simultaneously eliminating the formed di-n-propyl acetonitrile.