THE products obtained by sulphonation of m-cresol were first examined by Claus and Krauss (Ber., 1887, 20, 3089). A monosulphonic acid was formed by the action of concentrated sulphuric acid at 128" which gave crystalline salts and was shown to be m- creso3-6-sulphonic acid (Me: OH: SO, H= 1: 3: 6), as it readily yielded p-toluquinone on oxidation. This acid corresponds with phenol-p-sulphonic acid, the more stable of the two ...
