Formic acid and the high-temperature reductive desulfurization of aromatic sulfides

When diphenyl sulfide is heated with formic acid to 450/sup 0/C, it is converted to benzene, toluene, thiophenol, thioanisole, and benzoic acid. By increasing the time of reaction, diphenyl sulfide is converted completely to benzene and toluene. The mechanism of toluene and benzoic acid formation is studied by kinetic data and by comparing CO and CO/sub 2/ as possible sources for the extra carbon. It is concluded that PhS. and CO are the precursors to benzoic acid, toluene, thiophenol, and thioanisole. Formic acid reacts primarily via the metal surface of the reactor and most probably with radical initiation.