pMeC6H4SO2OH

pMeC6H4SO2OH, also known as p-toluenesulfonic acid or tosyl acid, is an organic sulfonic acid. It is a strong organic acid, stronger than sulfuric acid. The chemical formula indicates a methyl group attached to a benzene ring, with a sulfonic acid group at the para position. It typically appears as a white crystalline solid that is soluble in water, ethanol, and ether.

p-Toluenesulfonic acid is widely used as an acid catalyst in organic synthesis. Its strong acidity and relatively low volatility make it a convenient reagent for reactions such as esterification, acetal formation, and deprotection reactions. It is also employed in the production of dyes and pharmaceuticals. In some applications, it is used in its monohydrate form, p-MeC6H4SO2OH·H2O.

Due to its acidic nature, it can be corrosive. Proper handling procedures are recommended when working with this compound. It is important to store it in a dry place.