Sulphonic

Sulphonic refers to a functional group in organic chemistry characterized by the formula R-SO3H, where R is an organic substituent. This group consists of a sulfur atom double-bonded to two oxygen atoms, single-bonded to a hydroxyl group (-OH), and single-bonded to the organic radical. Sulfonic acids are a class of strong organic acids. They are typically more acidic than their analogous carboxylic acids. The SO3H group is highly polar and hydrophilic, making sulfonic acids and their derivatives soluble in water.

The parent compound, where R is a hydrogen atom, is sulfic acid, HSO3H, which is highly unstable and exists only in dilute aqueous solutions. The most common sulfonic acids are alkylsulfonic acids, such as methanesulfonic acid (CH3SO3H), and arylsulfonic acids, such as benzenesulfonic acid (C6H5SO3H). These compounds are synthesized through various methods, including the sulfonation of hydrocarbons with sulfuric acid or sulfur trioxide.

Sulfonic acids and their derivatives, such as sulfonyl chlorides (R-SO2Cl) and sulfonamides (R-SO2NR'R''), have numerous applications. They are used as catalysts in organic synthesis, as surfactants in detergents and emulsifiers, and as intermediates in the production of dyes, pharmaceuticals, and ion-exchange resins. The strong acidity and water solubility of sulfonic acids make them valuable reagents in various industrial processes.