Hitoshi Saima

Synthesis gas conversion utilizing mixed catalyst composed of CO reducing catalyst and solid acid

The synthesis of aromatic hydrocarbons from carbon monoxide and hydrogen was studied under pressurized conditions using hybrid catalysts composed of a methanol synthesis catalyst (Pd/SiO/sub 2/) and zeolites. Combination of Pd/SiO/sub 2/ with H-ZSM-5 or H-mordenite gave aromatic hydrocarbons with selectivities higher than 50%. Coupling of Pd/SiO/sub 2/ with H-Y gave little aromatics. Aromatic hydrocarbons formed on the H-ZSM-5 based catalyst, were mostly tetramethyl and pentamethyl benzenes, significantly different from those obtained by the reaction of methanol on the H-ZSM-5 alone. The yield of hydrocarbons was far higher than the level which is estimated from the thermodynamic equilibrium of methanol formation. The hydrocarbon formation was favored by the high reaction temperature and the high operating pressure. A reaction scheme of the hydrocarbon formation on the hybrid catalyst will be described which includes: formation of methanol, conversion of methanol to olefins, aromatization of olefins, hydrogenation of olefins on Pd/SiO/sub 2/, and methylation of aromatic hydrocarbons by methanol on zeolites.

Selective Synthesis of C3 and C4 Hydrocarbons from Synthesis Gas by Utilizing Hybrid Catalysts Containing Y-Type Zeolites

Synthesis gas was converted to C 3 and C 4 hydrocarbons with the selectivity as high as 74% and without making methane and aromatic hydrocarbons by utilizing hybrid catalysts composed of methanol synthesis catalysts and Y-type zeolites. The essentials of the high selectivity was the quick diffusion of olefins, which are the intermediates from methanol to paraffins, in zeolite pores and their quick hydrogenation on the methanol catalyst.

Dry Reforming of Dimethyl Ether with Carbon Dioxide over a Cu-Containing Hybrid Catalyst

Reforming of dimethyl ether with carbon dioxide into synthesis gas has been carried out over a mixed catalyst containing Cu-based methanol decomposition catalyst and alumina. The catalyst is found to show a high activity and selectivity. Catalyst stability and deactivation mechanism was also examined.