| 초록 |
Sulfur-free Ni-Mo catalysts have been synthesized using various types of compounds as a support, and were applied to the hydroconversion of fatty acid derivatives, which is obtained through the transesterification of triglycerides with alcohol. It was found that the physicochemical properties of support compounds significantly influenced not only the catalytic activity but the reduction processes of fatty acid derivatives. The size of Ni-Mo particles loaded on SiO2 was decreased with an increase in the surface area of SiO2 as a support, leading to improving the catalytic activity in the hydroconversion of methyl laurate (ML), while the product distribution was independent of the surface area of the SiO2 support; C11 hydrocarbons were dominantly produced followed by C12 hydrocarbons. The product distribution in the hydroconversion of ML was strongly dependent on the acid properties of support compounds. When acidic metal oxides such as SiO2-Al2O3 and TiO2 were used as a support, the Ni-Mo catalysts exhibited higher catalytic activity and selectivity to C12 hydrocarbons compared with the Ni-Mo catalysts prepared using basic metal oxides such as MgO and ZrO2 as a support. Furthermore, the Ni-Mo catalysts prepared with zeolites including beta zeolite, ZSM-5, and USY as a support produced dominantly C12 hydrocarbons followed by C11 hydrocarbons. It is thus suggested that fatty acid derivatives can be adsorbed on the support due to interactions of the carbonyl group of fatty acid derivatives with acid sites of the support, leading to accelerating the reduction of the carbonyl group with hydrogen activated on Ni species although in general the elimination of the carbonyl group, decarbonylation, easily occurs in the hydroconversion of fatty acid derivatives over Ni catalysts. |
