Benzonitrile is the chemical compound with the formula , abbreviated Phenyl. This aromatic organic compound is a colorless liquid with a cherry or almond like odour. It is mainly used industrially to synthesize the melamine resin precursor benzoguanamine.
Production and reactions
It is prepared by
ammoxidation of
toluene, that is its reaction with
ammonia and oxygen (or air) at .
- + 3/2 + → +
In the laboratory it can be prepared by the dehydration of
benzamide or benzaldehyde oxime
or by the Rosenmund–von Braun reaction using
cuprous cyanide or
Sodium cyanide/DMSO and
bromobenzene.
Hydrogenation of benzonitrile in principle gives benzylamine, but owing to transamination, dibenzylamine and tribenzylamine are also produced.
Applications
Laboratory uses
Benzonitrile is a useful solvent and a versatile precursor to many derivatives. It reacts with amines to afford N-substituted benzamides after hydrolysis.
It is a precursor to diphenylmethanimine via reaction with phenylmagnesium bromide followed by
methanolysis.
Benzonitrile forms coordination complexes with transition metals that are both soluble in organic solvents and conveniently labile. One example is . The benzonitrile ligands are readily displaced by stronger ligands, making benzonitrile complexes useful synthetic intermediates.
History
Benzonitrile was reported by Hermann Fehling in 1844. He found the compound as a product from the thermal dehydration of ammonium benzoate. He deduced its structure from the already known analogue reaction of
ammonium formate yielding
hydrogen cyanide (formonitrile). He also coined the name benzonitrile which gave the name to all the group of
.
In 2018, benzonitrile was reported to be detected in the interstellar medium.
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