Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

Reversible adsorption of heptane and benzene on model and industrial hydrodesulphurization molybdena catalysts has been studied by elution chromatographic method at 150 °C. An increase in the adsorption of heptane on sulphidation of adsorbents was small for Al₂O₃ and great for MoO₃. Supported catalysts behaved as mixture of Al₂O₃ and MoO₃.The portion of surface which can be transformed by sulphidation into MoS₂ ranged from 0 to 65% for individual commercial catalysts, as determined from the change in heptane adsorption after sulphidation of a given sample. The polarity of catalysts, including their acidity, was estimated from the difference between adsorption of benzene and heptane. The polarity of model and industrial catalysts in oxidic form was similar to that of alumina in most cases. The decrease in the polarity after sulphidation of the adsorbents was small for Al₂O₃ and great for MoO₃. The decrease in polarity resulting from sulphidation of supported catalysts was relatively small, since the reaction of MoO₃ monolayer with hydrogen sulphide leads to partial reformation of the alumina surface. The acidity of supported sulphided hydrodesulphurization catalysts has been shown by this method to be comparable with the acidity of the support itself.