Abstract
The activity of a commercial CoMo/Al2O3 catalyst was examined in the reaction of thiophene hydrodesulphurization. The catalytic measurements were performed in a gradientless flow circulating system at atmospheric pressure. It was found that preliminary coking of the catalyst lead to a considerable decrease of its hydrodesulphurization activity while the selectivity to butane increases. It is also found that the catalyst coking pretreatment reduces its surface, and the formation of monolayer coke and dendrites is observed. It's possible at special conditions of catalyst coking, to increase the selectivity and therefore output of some products in the reaction.