Catalytic Cracking of Ethanethiol over Various Solid Acid Catalysts

Experimental studies were carried out to determine what kind of catalysts are effective for the cracking of ethanethiol using a pulse reactor.Solid acid catalysts such as silica-alumina (SA), solid phosphoric acid (SPA), alumina (Al2O3), hydrogen Y zeolite (HY) and metal Y zeolite (MeY) showed a definite activity in the cracking of ethanethiol. However, solid bases such as CaO and MgO showed no activity.From these results, it may be said that the solid acid catalysts accelerate the cracking of ethanethiol. The cracking products of ethanethiol on SA, SPA, HY and MeY were only ethylene and hydrogen sulfide. In the case of ethanethiol cracking on Al2O3, the products were ethylene, hydrogen sulfide and a substantial amount of diethylsulfide which was formed by the disproportionation of ethanethiol.Furthermore, detailed studies were made on the effective active sites of the solid acid catalysts which showed the activity in the cracking of ethanethiol. And it was concluded that the active sites of SA, SPA and HY were the Bronsted acid sites, and that the active sites of Al2O3 were both Lewis acid sites and basic sites, and that the active sites of MeY were mainly the metal ions.In light of the nature of the active sites, reaction mechanisms were proposed for the cracking of ethanethiol over individual solid acid catalysts.