Collect. Czech. Chem. Commun. 1986, 51, 2770-2780

Hydrogenation-dehydrogenation and cleavage functions of hydrorefining catalysts studied by the reaction of tetrahydrothiophene

Alexandra Drahorádová and Miroslav Zdražil

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


The reaction of tetrahydrothiophene in a stream of nitrogen was used to study the relations between dehydrogenation and C-S cleavage reactions on sulphided Co-Mo/Al2O3 catalysts. The course of the reaction was compared for Co-Mo catalysts supported on alumina and activated carbon, for alumina alone as well as for a Pt/C catalyst. The effect of substitution of nitrogen for hydrogen, of the addition of water to the feed, of pre-sulphidation of catalysts and their deactivation by coking on the rate and selectivity of the reaction were also investigated. The results showed that hydrogenation-dehydrogenation and dehydrosulphurization activity of the sulphide catalysts have the same origin. Hydrogen accelerates dehydrosulphurization on the sulphide catalysts by removing sulphur and unsaturated hydrocarbons formed on catalyst surface by C-S bond cleavage reactions.