Sulfonat

Sulfonat, in English sulfonate, denotes the sulfonate group and related salts derived from sulfonic acids. The term covers both the conjugate base of a sulfonic acid and a range of sulfonate esters and salts.

Structure and properties: A sulfonate group comprises a sulfur(VI) center double-bonded to two oxygens and singly bonded to an alkyl or aryl group and to a negatively charged oxygen, giving the anion R-SO3−. Sulfonic acids R-SO3H are strong acids with pKa around -2 to 1; salts are typically ionic and water-soluble depending on substituents.

Preparation and types: Sulfonates can be generated by sulfonation of aromatic rings using sulfuric acid or chlorosulfonic acid to give arylsulfonic acids, which are then neutralized to form salts. Sulfonate esters such as tosylates and mesylates are formed by reaction of alcohols with sulfonyl chlorides (tosyl chloride, mesyl chloride); triflates are formed from trifluoromethanesulfonyl chloride.

Uses: Anionic surfactants include alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate. These compounds are widely used as detergents and dispersants. In organic synthesis, tosylates, mesylates, and triflates serve as excellent leaving groups. In biochemistry, sulfonate groups occur in taurine and in various sulfated carbohydrates and proteins.

See also: sulfonic acid, sulfate, sulfonamide, tosylate, mesylate, triflate.