Kenji Asami

Selective oxidative coupling of methane over supported alkaline earth metal halide catalysts

Abstract Halides of alkaline earth metals supported on calcium oxide or magnesium oxide were found to be excellent catalysts for the oxidative coupling of methane. For example, the selectivity with respect to C 2 hydrocarbons over a 5 wt.-% MgCl 2 /CaO catalyst reached 90% or higher with a yield of 10% at 750°C and CH 4 /O 2 =9. Although the selectivity with respect to C 2+ hydrocarbons gradually decreased with processing time, the in situ replenishment of the trace amount of halogen compound in the feed gas prevented this decrease. The halide ion in the catalyst is inferred to change the surface character of the alkaline earth metal oxide, reducing its ability for methane decomposition and resulting in suppression of the deep oxidation of methane.

Oxidative dimerization of dimethyl ether with solid catalysts

Abstract It was found that the oxidative coupling of dimethyl ether (DME) to dimethoxyethane was catalyzed by SnO2/MgO catalyst at around 200°C and 16 atm. The formation of 1,2-dimethoxyethane was favored for lower reaction temperatures, intermediate operating pressures and higher DME/O2 ratios. The reaction mechanism for the supported tin catalyst system was assumed to be based on a redox cycle.

Effect of a-strain on a synthesis of cis-fused 4a-aryloctahydro-1H-cyclopenta[c]pyridine derivatives through tandem radical cyclisation of an α-acylamino–polyene system

An efficient synthesis of the cis-fused 4a-aryloctahydro-1H-cyclopenta[c]pyridine ring sustem, an analogue of 4a-aryidecahydroisoquinoline, was achieved through a teandem redical approach by cyclisation of free radical–polyene species.

Selective Oxidative Coupling of Methane to Ethane and Ethylene

Abstract It has been found that lead oxide catalysts supported on basic carriers such as MgO or β-Al2O3 exhibit excellent activity and selectivity for the oxidative coupling of methane. Lattice oxygen is proved to be responsible for the formation of C2 hydrocarbon.

Oxidative coupling of methane in the homogeneous gas phase under pressure

Non-catalytic oxidative coupling of methane to give ethane and ethylene is considerably enhanced under pressures of up to 1.6 MPa in the temperature range 650–800 °C.

Synthesis of C2+ Hydrocarbons and Syngas by Gas Phase Methane Oxidation Under Pressure

Oxidative coupling of methane was conducted in the non-catalyzed gas phase system under pressurized conditions. Both partial pressures of oxygen and methane showed marked effects on either reaction rate or product selectivity. Low oxygen pressure was essential for high C2- selectivity. Additives such as CHCl2CHCl2, H2S, CH3COCH3, CO2 promoted C2 yield and the promoting mechanism seems different among these promoters. The carbon dioxide seemed to promote the reaction by the third body effects, without lowering the selectivity of C2 hydrocarbons.

Gas-phase oxidative coupling of methane in the presence of promoters

Study of the noncatalytic methane oxidation in pressurized vapor-phase with various promoters such as TCE, hydrogen sulfide and CH 3 COCH 3