Activation of a hydrorefining cobalt—molybdenum catalyst: II. Development of Polyfunctional Activity of the Catalyst During Activation

The development of the activity of a commercial hydrorefining CoMo/Al2O3 catalyst during its activation by reduction with hydrogen or by reductive sulphidation with a hydrogen-hydrogen sulphide mixture has been studied and compared with that of the surface groups and sites. Initial reaction rates of hydrogenation, dehydrogenation and skeletal isomerization of cyclohexane at 320°C, dehydrogenation and desulphurization of tetrahydrothiophene at 320°C, and desulphurization of tert.-butylmercaptan at 140°C and the rates of reactions of intermediate C4-olefins were followed and compared with the formation of surface hydroxyl and sulphhydryl groups and oxygen chemisorption sites. The presence of at least two main types of active centers has been revealed: coordinatively unsaturated sites of the first type for hydrogenation-dehydrogenation reactions and coordinatively unsaturated sites of the second type and sulphhydryl groups for CS and CC splitting reactions.