Single and competitive hydrodesulphurization of thiophene and benzo[b]thiophene on molybdenum catalysts

The reactivity of benzo[b]thiophene and thiophene and the amount of 2,3-dihydrobenzo[b]thiophene and tetrahydrothiophene in the title reaction on sulphided Co-Mo-Al2O3 and MoS2 catalysts has been determined at the temperature range 543-623 K and hydrogen pressures 0.5-2.0 MPa in a tubular flow integral reactor. Under above conditions, benzo[b]thiophene was more reactive than thiophene and the difference in their reactivities in the competitive reaction was substantially greater than in the single reaction. The selectivity to the intermediate 2,3-dihydrobenzo[b]thiophene and tetrahydrothiophene in the reaction of benzo[b]thiophene and thiophene respectively, was measured in the whole region of total conversion. Based on these and reported data, the mechanism of hydrodesulphurization is discussed.