ptoluenesulfonovou

p-Toluenesulfonic acid, often abbreviated as TsOH or PTSA, is a strong organic sulfonic acid with the chemical formula CH3C6H4SO3H. It is a white solid that is soluble in water and polar organic solvents. Its structure consists of a benzene ring substituted with a methyl group and a sulfonic acid group, with these substituents in a para (1,4) position relative to each other. It is commonly encountered as its monohydrate form, CH3C6H4SO3H·H2O.

p-Toluenesulfonic acid is widely used in organic synthesis as an acidic catalyst. Its strength as an acid, combined with its good solubility in organic solvents and its non-oxidizing nature, makes it a versatile alternative to mineral acids like sulfuric acid. It is frequently employed in reactions such as esterifications, acetal formations, and dehydration reactions. It can also be used to catalyze polymerization reactions. In some applications, it is used to convert alcohols into alkyl tosylates, which are excellent leaving groups for nucleophilic substitution reactions. The p-toluenesulfonate anion (tosylate) is a stable, non-nucleophilic counterion. It is produced industrially by the sulfonation of toluene.