Catalytic Propylene Production from Ethylene Using Zeolite Catalysts

摘要

Two new methods for the catalytic synthesis of propylene using solid acid catalysts are presented. The first approach is a new method for the activation of methane, involving conversion of methane to propylene over metal cations exchanged zeolites, such as silver-exchanged zeolite, in the presence of ethylene. In the second method, ethylene conversion proceeds directly and selectively over proton-exchanged zeolite. The heterolytic dissociation of methane over silver cationic clusters (Ag_n~+) in Ag~+-exchanged zeolites, leading to the formation of silver hydride (Ag_n-H) and CH_3~(d+) species, which reacts with ethene to form propene around 673 K. Using ~(13)C-labeled methane as a reactant, propene is shown to be a primary product from by methane and ethene. Thus, a significant proportion of propene was singly ~(13)C-labeled (~(13)CC2H6). H~+-exchanged zeolites, such as H-ZSM-5 do not catalyze the methane conversion, only ethylene being converted into higher hydrocarbons, such as propylene. Ethylene is selectively converted to propene over SAPO-34 at 723 K with a yield of 52.2 % and selectivity of 73.3 % at ethene conversion of 71.2 %.