benzoic acid
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benzoic acid
(bĕnzō`ĭk), C6H5CO2H, crystalline solid organic acid that melts at 122°C; and boils at 249°C;. It is the simplest aromatic carboxylic acid (see aryl grouparyl group, in chemistry, group of atoms derived from benzene or from a benzene derivative by removing one hydrogen that is bonded to the benzene ring (see radical). The simplest aryl group is phenyl, C6H5 ; it is derived from benzene.
..... Click the link for more information. and carboxyl groupcarboxyl group
, in chemistry, functional group that consists of a carbon atom joined to an oxygen atom by a double bond and to a hydroxyl group, OH, by a single bond. Carboxylic acids are compounds whose molecules contain a carboxyl group that is joined to a hydrogen atom, an
..... Click the link for more information. ). In addition to being synthesized from a variety of organic compounds (e.g., benzyl alcohol, benzaldehyde, toluene, and phthalic acid), it may be obtained from resins, notably gum benzoinbenzoin
or benzoinum
, balsamic resin, the dried exudation from the pierced bark of various species of the benzoin tree (Styrax) native to Sumatra, Java, and Thailand; appearing as red-brown to yellow-brown tears.
..... Click the link for more information. . It is used largely for making its salts and esters, most notably sodium benzoate, which is widely used as a preservative in foods and beverages and as a mild antiseptic in mouthwashes and toothpastes.
Benzoic Acid
the simplest aromatic acid, C6H5COOH; it forms clear, lustrous crystals. It was first isolated by sublimation at the beginning of the 17th century from benzoic resin (benzoin gum), hence its name. Its melting point is 122° C. Benzoic acid is readily soluble in organic solvents; it is poorly soluble in water. It sublimates readily and is distilled with steam. Benzoic acid is obtained by the oxidation of toluene with nitric or chromic acid, as well as by the decarboxylation of phthalic acid.
Benzoic acid in the form of complex esters and salts is contained in various natural essential oils—for example, clove oil. In medicine it is used externally in cases of skin diseases as an antiseptic and fungicidal agent; its sodium salt is used as an expectorant. In addition, the sodium salt is used in the preservation of foodstuffs. The esters of benzoic acid (from methyl to amyl), which have a strong odor, are used in the perfume industry. Various derivatives of benzoic acid— for example, chlorobenzoic and nitrobenzoic acids—are used in the synthesis of dyes.