p-Toluenesulfonic acid

p-Toluenesulfonic acid (PTSA or pTsOH) or tosylic acid (TsOH) is an organic compound with the formula CH₃C₆H₄SO₃H. It is a white solid that is soluble in water, alcohols, and other polar organic solvents. The CH₃C₆H₄SO₂– group is known as the tosyl group and is often abbreviated as Ts or Tos. Most often, TsOH refers to the monohydrate, TsOHH₂O.