Sulfonaattiryhmän

Sulfonaattiryhmän, often referred to as the sulfonate group, is a functional group in organic chemistry with the general formula R-SO3-. Here, 'R' represents an organic substituent, which can be an alkyl, aryl, or other organic radical. The sulfur atom in the sulfonate group is in its highest oxidation state, +6. This group is derived from sulfonic acids, which have the general formula R-SO3H. When the acidic proton is removed, the sulfonate anion R-SO3- is formed.

Sulfonate groups are characterized by their strong acidity. Sulfonic acids are among the strongest organic acids, comparable in strength to sulfuric acid. The sulfonate anion is a very stable, weakly basic conjugate base. This stability arises from the delocalization of the negative charge over the three oxygen atoms and the electronegativity of the oxygen atoms.

The presence of a sulfonate group significantly influences the properties of an organic molecule. It generally increases water solubility due to its polar nature and ability to form hydrogen bonds with water. This property is exploited in the synthesis of detergents, dyes, and surfactants, where sulfonate groups are often incorporated to enhance water miscibility. Examples include sodium dodecylbenzenesulfonate, a common surfactant. Sulfonate groups can also act as good leaving groups in certain organic reactions, facilitating nucleophilic substitution.