Isobutyronitrile

Description

Isobutyronitrile, often called isopropyl cyanide, is a highly toxic liquid with the aroma of almonds. An early synthesis of the compound from isobutyl alcohol and ammonia was reported by Tohoru Hara and Shigeru Komatsu at Kyoto Imperial University in 1925. Today, isobutyronitrile is generally made by passing isobutyl alcohol or isobutyraldehyde and ammonia over a suitable catalyst at high temperatures.
Isobutyronitrile has only a few uses. It is an industrial solvent and a starting material for producing insecticides such as diazinon. Recently, several patents mention isobutyronitrile as a cosolvent in battery electrolytes.
Despite its relative obscurity, isobutyronitrile made big news in 2014, when astronomers detected it in the interstellar medium. Hundreds of other molecules have been found in space, but isobutyronitrile was unique in that its carbon chain is branched, as opposed to linear. Using the then-new Atacama Large Millimeter/submillimeter Array telescope in Chile, Arnaud Belloche and colleagues at the Max Planck Institute for Radio Astronomy (Bonn, Germany) found the molecule in a massive star-forming region called Sagittarius B2.
This finding was especially significant because it may be a clue that branched-chain amino acids are also present in star-forming regions.

Chemical properties

Colorless liquid with a foul odor. Insoluble in water, easily soluble in ethanol and ether.

The Uses of Isobutyronitrile

Isobutyronitrile can be derived from isobutyraldehyde. It is used in organic synthesis, as a catalyst in the polymerization of ethylene and in the petroleum industry as a gasoline additive. Isobutyronitrile is also used to synthesize the intermediate 2-isopropyl-4-methyl-6-hydroxypyrimidine of the organophosphorus insecticide diazinon.

Production Methods

Isobutyronitrile is prepared from isobutyraldehyde by cyanation with ammonia.

Definition

ChEBI: Isobutyronitrile is an aliphatic nitrile that is acetonitrile in which two of the hydrogens have been replaced by methyl groups. It has a role as a polar aprotic solvent. It is an aliphatic nitrile and a volatile organic compound.

Production Methods

Isobutyronitrile is usually obtained by the catalytic gas-phase reaction of isobutyraldehyde or isobutanol with ammonia. Its major use is the synthesis of the insecticide diazinon.

General Description

A clear colorless liquid. Flash point 47°F. Less dense than water. Vapors heavier than air. Toxic oxides of nitrogen produced during combustion.

Air & Water Reactions

Highly flammable. Slightly soluble in water.

Reactivity Profile

Isobutyronitrile is incompatible with the following: Oxidizers, reducing agents, strong acids & bases .

Hazard

Toxic by ingestion, inhalation, and skin absorption.

Health Hazard

Isobutyronitrile is considered highly hazardous and full precautions should be taken to prevent skin contact or inhalation of vapor. Inhaled isobutyronitrile is about 2.4 times as toxic as acetonitrile in rats. may be fatal if inhaled, swallowed, or absorbed through skin. Contact may cause burns to skin and eyes. (Non-Specific -- Nitriles) Primarily, they are skin and eye irritants. Large doses cause collapse and stop breathing. In order to protect workers, the recommended TWA limit is obtained by dividing that for acetonitrile by the factor 2.4. NIOSH has therefore recommended that employee exposure should not exceed 8 p.p.m. (22 mg/m3) for either compound as a TLV-TWA.

Fire Hazard

Vapor may explode if ignited in an enclosed area. Toxic oxides of nitrogen are produced during combustion. Isobutyronitrile is a flammable/combustible material and may be ignited by heat, sparks, or flames. Vapors may travel to a source of ignition and flash back. Container may explode in heat of fire. Vapor explosion and poison hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Hazardous polymerization may not occur.

Metabolism

Thiocyanate was present in the urine of rats dosed orally with isobutyronitrile.

Purification Methods

Shake the nitrile with conc HCl (to remove isonitriles), then with water and aqueous NaHCO3. After a preliminary drying with silica gel or Linde type 4A molecular sieves, it is shaken or stirred with CaH2 until hydrogen evolution ceases, then decanted and distilled from P2O5 (not more than 5g/L, to minimize gel formation) or Drierite (b 101-103o/760mm). Finally it is refluxed with, and slowly distilled from CaH2 (5g/L), taking precautions to exclude moisture. [Beilstein 2 H 294, 2 I 129, 2 II 263, 2 III 655, 2 IV 853.]