SORPTION ON HYDRODESULFURIZATION CATALYSTS

The adsorption of hydrocarbons, thiophenes, esters, acids, and anilines on MoS2 and on sulfurized CoMoAl2O3 and Al2O3 catalysts has been investigated by a chromatographic method at 200 °C. The polarity of catalysts, estimated from differences in the adsorption of alkanes and aromatic hydrocarbons, decreases in the order Al2O3 > CoMoAl2O3 > MoS2. This order correlates with the ratio of the activity for H2S elimination from saturated sulfur compounds (proceeding without participation of hydrogen) to the hydrogenation-dehydrogenation activity of the catalysts which decreases in the same sequence. The nonspecificity of the MoS2 surface compares with the surface of graphitized carbon black, and both acids and anilines are eluted easily from this surface. Adsorption capacities of alkanes at the origin of the isotherm, related to unit BET surface, differ for individual catalysts. These are 9:3:1 for MoS2:CoMo Al2O3:Al2O3, respectively, this ratio being little dependent upon the n-alkane used for comparison (C7C10). The pore distribution has been determined from the desorption branch of N2 isotherm. The surface of CoMoAl2O3 catalyst consists of pores which are approximately five times smaller than those of MoS2 and Al2O3 catalysts. © 1979.