phenylcarboxamide

Phenylcarboxamide, commonly called benzamide, is the amide derived from benzoic acid and ammonia. In systematic terminology it is benzenecarboxamide. The term phenylcarboxamide can also refer more broadly to amides in which the acyl portion is a phenylcarbonyl group, but the parent compound most frequently corresponds to Ph-CO-NH2.

The chemical formula of benzamide is C7H7NO, and it typically appears as a white to colorless crystalline solid. It has a melting point of about 128–131°C and is only slightly soluble in water, with greater solubility in many organic solvents such as ethanol, acetone, and dichloromethane. The molecule contains a carbonyl group adjacent to a phenyl ring and an amide NH2 group capable of hydrogen bonding.

Preparation of benzamide is most often achieved by converting benzoic acid to its amide. Common routes include reacting benzoic acid with ammonia to form benzamide directly, or first converting benzoic acid to benzoyl chloride and then treating the acyl chloride with ammonia. Other, less common methods include ammonolysis of esters or catalytic transformations of related precursors.

Derivatives of benzamide arise by substituting the amide nitrogen or by modifying the benzenecarbonyl portion. N-substituted benzamides, such as N-phenylbenzamide, are important as intermediates in organic synthesis and in medicinal chemistry. The benzamide carbonyl group is also a site for reduction to give primary amines (e.g., reduction to aniline).

Applications and safety: Benzamide serves as a versatile building block in chemical synthesis, including pharmaceutical and dye chemistry. It is generally of low to moderate acute toxicity; standard laboratory safety practices should be followed to minimize inhalation, ingestion, or dermal exposure.