Oxidative ethane activation over oxide supported molten alkali metal chloride catalysts

摘要

Oxidative dehydrogenation of ethane was studied with Li/Dy/Mg/Cl mixed oxides with various Cl~- loadings as catalyst. Ethylene yields of up to 77% were obtained with catalysts containing above 8 wt% Cl~-. Based on kinetic data and in situ high-temperature XRD measurements as well as TG-DSC analysis, a new reaction model is proposed. The active species of the catalytic system are postulated to be dissolved in molten LiCl, supported on Dy_2O_3/MgO. Atomic oxygen in the LiCl melt is speculated to form the catalytically active [OCl~-] species. The decomposition of [OCl~-] leads to the formation of O· + Cl~- or O~- + Cl·. Both radical species are highly oxidizing and readily activate alkanes via hydrogen abstraction.