3Toluenesulfonic

3-Toluenesulfonic acid, also known as meta-toluenesulfonic acid, is an organic compound with the chemical formula CH3C6H4SO3H. It is a derivative of toluenesulfonic acid, where the sulfonic acid group is positioned at the meta position (carbon 3) relative to the methyl group on the benzene ring. It is a strong acid and is typically encountered as a solid or in aqueous solution. Its appearance is often white or off-white crystals.

This compound finds various applications in organic synthesis. It can act as an acid catalyst in reactions such as esterification, etherification, and acetal formation. Its solubility in organic solvents makes it a useful alternative to inorganic acids in certain non-aqueous reactions. 3-Toluenesulfonic acid is also used in the production of dyes and pharmaceuticals. In some contexts, it may be employed as a sulfonation agent, although other reagents are often preferred for direct sulfonation of aromatic rings.

The preparation of 3-toluenesulfonic acid can be achieved through the sulfonation of toluene. Controlling the reaction conditions, such as temperature and the choice of sulfonating agent, is crucial to favor the meta isomer over ortho and para isomers. Purification methods typically involve recrystallization. Like other strong acids, it is corrosive and should be handled with appropriate safety precautions.