Collect. Czech. Chem. Commun. 1986, 51, 1195-1205

The effect of Co in hydrodesulphurization of 2,3-dihydrobenzo[b]thiophene on Co-Mo catalyst

Rudolf Peter, Vlastimil Matějec and Miroslav Zdražil

Institute of Chemical Process Fundamentals, Czechoslovak Academy of Sciences, 165 02 Prague 6 - Suchdol


Hydrodesulphurization of benzo[b]thiophene and 2,3-dihydrobenzo[b]thiophene on Mo/alumina and Co-Mo/alumina catalysts has been studied in a flow reactor at atmospheric pressure and temperature 543 K. The amount of dihydrobenzo[b]thiophene formed in hydrodesulphurization of benzo[b]thiophene and the amount of benzo[b]thiophene formed in hydrodesulphurization of dihydrobenzo[b]thiophene were much lower on Co-Mo catalyst then on Mo catalyst. The equilibrium constant of the hydrogenation of benzo[b]thiophene to dihydrobenzo[b]thiophene at 543 K was determined. This partial equilibrium was attained during hydrodesulphurization on Mo catalyst irrespectively of the fed sulphur compound but was not approached during hydrodesulphurization on Co-Mo catalyst. Kinetic equation describing simultaneously the reaction of both heterocycles was derived from consecutive hydrogenation-elimination scheme which does not contain step referred to as direct hydrogenolysis of the thiophenic ring. It was concluded that the effect of Co in the reaction network is localized in the section between partially hydrogenated benzothiophene and hydrogen sulphide