sulfonointireaktioilla

Sulfonointireaktioilla, or sulfonation reactions, are a class of chemical reactions in which a sulfonic acid group (SO3H) is introduced into an organic molecule. This process is typically achieved by treating the organic compound with a sulfonating agent, most commonly concentrated sulfuric acid (H2SO4) or fuming sulfuric acid (oleum), which is sulfuric acid containing dissolved sulfur trioxide (SO3). Other sulfonating agents like chlorosulfonic acid (ClSO3H) can also be used.

Sulfonation is an electrophilic aromatic substitution reaction when applied to aromatic compounds. The electrophile is sulfur trioxide (SO3), which is generated in situ from sulfuric acid. The sulfur trioxide then attacks the electron-rich aromatic ring, forming a sigma complex, which subsequently loses a proton to regenerate aromaticity and form the sulfonic acid derivative. The position of sulfonation on an aromatic ring is influenced by existing substituents, following the rules of electrophilic aromatic substitution.

Sulfonic acids and their derivatives are important intermediates in organic synthesis. They are used in the production of dyes, pharmaceuticals, detergents, and ion-exchange resins. The sulfonic acid group is highly polar and water-soluble, which can be exploited to increase the solubility of organic molecules. Furthermore, the sulfonic acid group can be readily converted into other functional groups, such as sulfonyl chlorides or sulfonamides, expanding their synthetic utility.