Mechanistic Investigations on the Direct Regioselective Sulfonation of Gaseous Light Hydrocarbons by Sulfur Dioxide

Gaseous light hydrocarbons (LHs) are traditionally used as fuels, while their functionalization leads to wide applications of high economical values. Presented herein is the direct sulfonation of gaseous LHs by using SO2 and O2 gases. The in situ generated trifluoroperacetic acid (TFAOOH) and bis(trifluoroacetyl) peroxide ((TFAO)2) furnished the radical propagators trifluoroacetoxyl radicals (TFAO•) and HO•. The resultant trifluoroacetylsulfuric acid (TFAOSO3H) efficiently sulfonated LHs under mild conditions and in good chemoselectivities.