Sulfonointireaktio

Sulfonointireaktio, often translated as sulfonation reaction, is a chemical process where a sulfonic acid group (SO3H) is attached to an organic molecule. This is typically achieved by reacting the organic substrate with a sulfonating agent. Common sulfonating agents include concentrated sulfuric acid, oleum (fuming sulfuric acid), and sulfur trioxide.

The reaction mechanism usually involves electrophilic aromatic substitution when applied to aromatic compounds. In this case, sulfur trioxide, or a protonated form of it, acts as the electrophile. The pi electrons of the aromatic ring attack the electrophile, forming a carbocation intermediate. Subsequently, a proton is lost from the ring, restoring aromaticity and yielding the sulfonic acid derivative.

Sulfonation is a reversible reaction, and the position of the equilibrium can be influenced by factors like temperature and the concentration of sulfuric acid. Sulfonic acids are strong acids and are often soluble in water. This property makes them useful as intermediates in the synthesis of dyes, detergents, and pharmaceuticals. For example, the sulfonation of benzene is a key step in the production of phenol and aniline. The introduction of a sulfonic acid group can also modify the properties of a molecule, such as increasing its water solubility or reactivity.