Akira Iino

Effect of cobalt on the sulfiding temperature of CoOMoO3/Al2O3 studied by temperature programmed sulfiding

Abstract The effect of cobalt on the sulfiding temperature of CoO MoO 3 /Al 2 O 3 was investigated by means of temperature programmed sulfiding (TPS). MoO 3 supported on alumina transforms into MoS 2− x by sulfidation via formation and subsequent hydrogenation of Mo oxi-sulfide or MoS 3 . The temperature of which the Mo oxi-sulfide or MoS 3 phase are hydrogenated (Ps temperature) decreased with increasing amount of cobalt in the CoO MoO 3 /Al 2 O 3 catalysts. A decrease in the Ps temperature was also observed in the case of ‘ Co/Al+ Mo/Al catalysts’ which were prepared by mechanical mixing of CoO/Al 2 O 3 and MoO 3 /Al 2 O 3 . On the other hand, the Ps temperature did not change by mechanical mixing of bulk CoO and the MoO 3 /Al 2 O 3 catalyst. The cobalt adsorption test suggested that the cobalt species preferably interact with the molybdenum species during impregnation. It was concluded that the well dispersed cobalt species have a capability to provide spillover hydrogen to accelerate the hydrogenation of the Mo oxi-sulfide. Furthermore, a correlation between the Ps temperature and HDS activity for light gas oil was obtained. This result suggests that the cobalt species facilitate the hydrogenation of sulfur atoms adsorbed on the HDS active sites (coordinatively unsaturated Mo sites) by supplying spillover hydrogen and consequently accelerate the HDS reaction.

Hydrocracking of residual oils with iron supported zeolite containing catalyst

Abstract Hydrogen spillover on a hydrocracking catalyst containing an iron supported Y zeolite has been studied. An iron supported Y zeolite was prepared by treating NH 4 -Y zeolite with aqueous solution of ferric nitrate. The iron supported zeolite showed high toluene dispropor-tionation activity in the presence of hydrogen and hydrogen sulfide, while it was poisoned by potassium ion exchange. A hybrid catalyst prepared by physically mixing a USY and the poisoned iron supported zeolite showed the high disproportionation activity, while the USY and the poisoned iron supported zeolite showed low activity. It was suggested that spillover hydrogen is supplied from iron species to Bronsted acid sites on zeolites to promote acid catalyzed reaction. In the case of hydrocracking catalyst composed of transition metals, iron supported zeolite and alumina, spillover hydrogen is also supplied from transition metals on alumina to zeolite surface to promote acid catalyzed reaction.

Active Sites of Novel Iron Supported Y-Type Zeolite

Abstract A novel iron supported Y-type zeolite prepared by treating NH 4 Y with ferric nitrate solution under low pH condition (FeHY) showed high activity for toluene disproportionation in the coexistence of H 2 S and H 2 . Active sites of FeHY for toluene disproportionation were investigated by elucidating function of iron cluster and zeolite separately. The activity of FeHY was significantly decreased by potassium ion exchanging (K/FeHY). Ultra stable Y-type zeolite (USY) also showed low activity. However, catalyst prepared by mixing K/FeHY and USY mechanically showed extremely higher activity than the sum of both catalysts. It was suggested that the active sites of FeHY are Bronsted acid sites in zeolite framework and that iron clusters supply spillover hydrogen to prevent zeolite from deactivation due to coke deposition.

New Method of Modifying Y-type Zeolite—Fe Supported Zeolite

An iron supported Y-type zeolite which was prepared from modifying NH4Y with ferric nitrate solution showed high activity for toluene disproportionation under the flow of H 2 S/H 2 . Detailed investigations found that preparation conditions such as temperature and Fe 3+ concentration significantly affect catalytic activity. The catalyst which was prepared by modifying NH 4 Y with 0.25M Fe(NO 3 ) 3 solution at 323K showed the highest activity among the tested samples.