What Is Benzonitrile?
Benzonitrile, an aromatic cyanide with the formula C6H5CN, was identified by Hermann von Fehling in 1844 during the decomposition of ammonium benzoate. This discovery led to the term “nitrile” for similar compounds. Classified under various regulations as a hazardous substance, a flammable liquid, and a deleterious substance, it requires careful handling.
Uses of Benzonitrile
As a versatile chemical, benzonitrile serves as a precursor to benzoic acid, benzylamine, and triazine rings through various reactions. Its applications span from plastics manufacturing to pharmaceutical and agricultural intermediates, solvents for antioxidants, plating solutions, dye construction, and epoxy resin curing agents.
Properties of Benzonitrile
This colorless liquid features an almond-like scent, a melting point of -13°C, and boils between 188-191°C. It’s flammable, with a flash point of 75°C and an ignition point of 550°C, soluble in alcohols and ethers, yet only 1% soluble in water at 100°C.
Structure of Benzonitrile
Known as phenyl cyanide, its structure includes a benzene ring with a cyano group substituting one hydrogen atom, abbreviated as PhCN. It has a molar mass of 103.04 g/mol and a density of 1.0 g/ml.
Other Information on Benzonitrile
1. Synthetic Methods
Benzonitrile is produced industrially by the ammoxidation of toluene and can be synthesized in the lab through dehydration of benzamide or benzaldehyde oxime. It’s also obtained via Rosenmund-von Braun synthesis or by diazotizing aniline in the Sandmeyer reaction.
2. Benzonitrile Reaction
Hydrolysis converts benzonitrile to benzoic acid, while reactions with amines yield N-substituted benzamides. It forms complexes with late transition metals, such as bis(benzonitrile)palladium dichloride, a yellowish-brown solid used in organic synthesis, showcasing its role as a convenient synthetic intermediate.