Yasuharu Kanda

Effects of Support on Formation of Active Sites and Hydrodesulfurization Activity of Rhodium Phosphide Catalyst

リン化ロジウム（Rh2P）触媒の活性点形成とその水素化脱硫（HDS）活性に対する担体の影響について検討した。担体には金属酸化物（MOx: SiO2，Al2O3，TiO2，MgOおよびZrO2）を用いた。いずれの担体の場合でも担持ロジウム－リン（Rh–P）触媒を水素還元するとRh2Pが生成した。一方，Rh2Pの生成温度は担体により異なった。このRh–P触媒のHDS活性は還元温度によって大きく変化した。最適な温度で還元したRh–P/MOx触媒のHDS活性の序列はSiO2～TiO2～Al2O3＞MgO＞ZrO2となった。また，還元温度を上昇させるとRh–P/MOx触媒のTOFは増加し，これはRh2Pが生成したためであることが分かった。Rh–P/MOx触媒のTOFの序列はTiO2＞ZrO2＞Al2O3＞SiO2＞MgOとなり，これはチオフェン転化率の序列とは一致しなかった。Rh–P/TiO2触媒が高いTOFを示した原因としては，部分的に硫化されたTiO2の生成が挙げられる。一方，Rh–P/MgO触媒のTOFが低かったのは，MgOは塩基性担体であり耐硫黄性が低かったためと考えられる。

Catalytic performance of noble metals supported on Al2O3-modified MCM-41 for thiophene hydrodesulfurization

Pt/4wt%Al2O3-MCM-41 catalyst showed high and stable activity for hydrodesulfurization of thiophene at 350°C and this activity was higher than that of commercial CoMo/Al2O3 hydrodesulfurization catalyst. Pt/4wt%Al2O3-MCM-41 catalyst has high hydrogenating ability in the hydrodesulfurization of thiophene. The Bronsted acid sites of Al2O3-MCM-41 and the spillover hydrogen formed on Pt particle in Pt/Al2O3-MCM-41 catalyst play an important role for the hydrodesulfurization of thiophene.

Catalytic performance of mesoporous silica SBA-15-supported noble metals for thiophene hydrodesulfurization

The Pt/AlSBA-15 catalyst showed high and stable catalytic activity for the hydrodesulfurization of thiophene at 350°C and this activity was higher than those of Pt/SBA-15 and commercial CoMo/Al2O3 catalysts. The Pt/AlSBA-15 catalyst has high sulfur-tolerant property toward hydrogen sulfide formed in hydrodesulfurization of thiophene. The Broensted acid sites of AlSBA-15 and the spillover hydrogen formed on Pt particle in Pt/AlSBA-15 catalyst play an important roles for the hydrodesulfurization of thiophene.

Solution Synthesis of N,N-Dimethylformamide-Stabilized Iron-Oxide Nanoparticles as an Efficient and Recyclable Catalyst for Alkene Hydrosilylation

Highly activated, monodispersed N,N‐dimethylformamide (DMF)‐stabilized iron‐oxide nanoparticles (Fe2O3 NPs) were synthesized by using iron(III) acetylacetonate as a precursor under open‐air conditions. The resulting Fe2O3 NPs were characterized by various techniques (e.g., transmission electron microscopy, dynamic light scattering, X‐ray diffraction, X‐ray photoelectron spectroscopy, FTIR spectroscopy, and X‐ray adsorption near‐edge structure). The Fe2O3 NPs exhibited efficient catalytic activity for the hydrosilylation of alkenes without the need for further additives. An effective recycling process of the colloidal catalyst by extraction with a hexane/DMF system was developed, and recycling of the catalyst over five cycles did not result in any significant loss in catalytic activity.