Description

Benzenesulfonic acid:

Benzenesulfonic acid is an organic compound with the formula C6H5SO3H. It is the simplest aromatic sulfonic acid.

Benzenesulfonic acid forms colorless deliquescent sheet crystals or a white waxy solid that is soluble in water and ethanol, slightly soluble in benzene and insoluble in carbon disulfide and diethyl ether. It is often stored in the form of alkali metal salts. Its aqueous solution is strongly acidic. It has the ability to react violently with bases and attack metals.

The alkali metal salt of benzenesulfonic acid is used in the production of phenol and resorcinol. Benzenesulfonic acid is also used as an acidic catalyst in esterification and dehydration reactions.

Benzenesulfonic acid reacts with phosphorus pentoxide to form benzenesulfonic acid anhydride (C6H5SO2OSO2C6H5), and may be converted to the corresponding acid chloride benzenesulfonyl chloride (C6H5SO2Cl) with phosphorus pentachloride.

A variety of pharmaceutical drugs are prepared as salts of benzenesulfonic acid and are known as besylates or besilates.

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