Acidic zeolites and Al-SBA-15 as supports for sulfide phases: application to hydrotreating reactions

摘要

Hydrotreating catalysts were prepared by supporting molybdenum,nickel molybdenum or nickel tungsten sulfides on HBEA zeolites or Al-SBA-15 mesoporous materials.The effect of the acidity (strength and number of acidic sites) on the properties of the sulfide phases and on their catalytic activity was discussed.An effect of the zeolite acidity on the electronic properties of the MoS_2 phase was observed,leading to a considerable enhancement in the hydrogenation and hydrodesulfurization activity.On the other side,for nickel molybdenum sulfide catalysts supported on an Al-SBA-15 support,no effect of acidities on hydrodesulfurization activity was observed.This result was assigned to the mild Bronsted acidity of Al-SBA-15.However,compared to silica support or commercial silica-alumina,an improvement of the hydrocracking activity (n-decane hydrocracking) of the nickel tungsten sulfide phase (NiWS) and isomerization selectivity (4,6-dimethyldibenzothiophene hydrodesulfurization) of the nickel molybdenum phase (NiMoS) was observed for the Al-SBA-15 supports.