Methanesulfonic acid (MsOH) is a colorless liquid with the chemical formula CH3SO3H. It is the simplest of the alkylsulfonic acids.Salts and esters of methanesulfonic acid are known as mesylates (or methanesulfonates, as in ethyl methanesulfonate). It ishygroscopic in its concentrated form. Methanesulfonic acid may be considered an intermediate compound between sulfuric acid(H2SO4), and methylsulfonylmethane ((CH3)2SO2), effectively replacing an -OH group with a -CH3 group at each step. This pattern can extend no further in either direction without breaking down the -SO2 group. Methanesulfonic acid can dissolve a wide range of metal salts, many of them in significantly higher concentrations than in hydrochloric or sulphuric acid.