Infrared spectroscopic investigation for catalytic desulfurization of organic sulfur compounds

Various kinds of zeolites, such as Na-zeolites, HY and MeY, showed catalytic activity for the cracking of ethanethiol; and the products were ethylene and hydrogen sulfide except on NaX. A substantial amount of diethylsulfide together with ethylene and hydrogen sulfide was formed in the ethanethiol cracking on NaX. HY and MeY, but not Na zeolites, showed activity for the cracking of thiophene without gas phase hydrogen; and the products were predominantly hydrogen sulfide. The infrared spectra of ethanethiol and thiophene adsorbed on zeolites suggest that the adsorption states of ethanethiol and thiophene on zeolites depend on the acidic characteristics of zeolites and, in all cases, there is the interaction between these organic sulfur compounds and the surface hydroxyl group or surface oxygen anion of zeolites. It is, thus, concluded that the surface hydroxyl group or surface oxygen anion of zeolites plays an important role for the adsorption of these organic sulfur compounds. Models of adsorption states and the cracking mechanism of ethanethiol and thiophene on zeolites were proposed on the basis of obtained infrared spectra. 3 figures, 2 tables.