Trifluoromethane sulphonic acid was found to desulphurize coal in the presence of hydrocarbon without hydrogen gas at as low as 150-200℃ for 3h under autogeneous pressure of 2.6-6.6MPa. No solvent or isopentane provided lower desulphurization of 19.8 or 23.4%, respectively, while toluene did 48.7% desulphurization.
