benzaldehyde(redirected from benzenecarbaldehyde)
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an organic compound, C6 H5 CHO; a colorless, oily liquid with the odor of bitter almonds; Tm = –26° C; Tb = 179° C. Benzaldehyde dissolves in water in the proportions of 0.3 g : 100 g; it is miscible with alcohol, ether, and other organic solvents. Benzaldehyde is easily oxidized (even in air) into benzoic acid, C6H5COOH; however, the addition of 0.1 percent hydroquinone inhibits oxidation. Benzaldehyde combines with sodium bisulfite, hydrocyanic acid, and other molecules by a CO bond. When benzaldehyde is boiled with an alkaline solution, benzyl alcohol and benzoic acid are formed (the Cannizzaro reaction). In the presence of the CN ion, benzaldehyde enters into benzoin condensation. The condensation of benzaldehyde with acetaldehyde under the action of a base yields cinnemal-dehyde, C6H5CH=CHCHO; condensation with phenols and aromatic amines yields derivatives of triphenylmethane.
Benzaldehyde in the form of a glycoside of amygdalin, which breaks down in water to form benzaldehyde, glucose, and hydrocyanic acid, is contained in the pits of bitter almonds and apricots, peaches, and other fruits. Benzaldehyde is obtained by the oxidation of toluene or the hydrolysis of benzylidene chloride, C6H5CHCl2. The method of obtaining benzaldehyde from benzene and carbon monoxide under the action of aluminum chloride is of great significance. Benzaldehyde is used as a fragrant substance, for the synthesis of cinnemaldehyde and benzoin, and in the production of dyes of the triphenylmethane series.
IA. F. KOMISSAROV