CONVERSION OF THIOPHENE ON MOLYBDENA-ALUMINA CATALYSTS CONTAINING GROUP 8-10 METALS - EFFECT OF H2S UPTAKE

Ageing and the effect of H2S on the activity and selectivity of Co-, Ru-, Pd-, Ir- and Pt-promoted and unpromoted MoOx-Al2O3 catalysts have been studied in relation to decomposition of thiophene. The overall activity increased on unpromoted and Pd-promoted molybdena-alumina, whereas on other catalysts it decreased substantially. The selectivity of production of butane and of fragmented hydrocarbons decreased on all catalysts. The changes in catalytic behaviour were caused by the uptake of H2S added to the system and produced in hydrodesulfurization (HDS) of thiophene. The results indicate no direct correlation between the propensity to interact with H2S and the HDS activity. It follows from data on changes in selectivity and activity, that metal and molybdena act predominantly independently at the early stages of sulfidation.