The catalytic activities of CoMoAl2O3 catalysts and of their components in the thiophene hydrodesulfurization reaction (HDS) were studied by a flow circulation technique. Catalysts in the oxidic form with CoMoO4 as the main phase are shown to possess the highest activity for the thiophene HDS reaction. Adsorption of H2, thiophene, and of their mixture on sulfided CoMoO4 and technical CoMoAl2O3 catalysts was investigated by TPD. H2 is adsorbed both molecularily and dissociatively on the catalysts studied, while thiophene is molecularily adsorbed. Desorption activation energies for the different H2 and thiophene forms were measured. The thiophene HDS reaction involves high-temperature forms of adsorbed thiophene, while hydrogenation of unsaturated hydrocarbons (butenes) involves high-temperature forms of adsorbed hydrogen. A scheme of the thiophene HDS reaction on sulfided CoMoO4 and technical CoMoAl2O3 catalysts is suggested on the basis of the results obtained.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry