The catalytic oxydehydrogenation (OXD) of ethanehas been investigated over a Cd-exchanged zeolite type 4A. Taking advance of the unique characteristics of the sieve towards separation of ethylene, which is more strongly held, the OXD of ethane is shown to occur in flow conditions (T = 460-515 °C, contact time, W/F = 0.05-0.425 min-1) with a good selectivity to ethylene and conversion of ethane up to 50 %. The results are interpreted assuming a reactivity sequence r, as following: rH2> rC2H6 >> rC2H4 which is the opposite of the heats of adsorption Hads C2H4> Hads C2H6 >> Hads H2 as derived from independent chromatographic and spectroscopic information. This is a good example of selective zeolite catalysts with adsorption characterestics for competing molecules under conditions (OXD) which overcome the thermodynamic limitations of standard dehydrogenation reactions.
Catalytic oxydehydrogenation of ethane over Cd-exchanged zeolites
OTTANA', Rosaria;
1983-01-01
Abstract
The catalytic oxydehydrogenation (OXD) of ethanehas been investigated over a Cd-exchanged zeolite type 4A. Taking advance of the unique characteristics of the sieve towards separation of ethylene, which is more strongly held, the OXD of ethane is shown to occur in flow conditions (T = 460-515 °C, contact time, W/F = 0.05-0.425 min-1) with a good selectivity to ethylene and conversion of ethane up to 50 %. The results are interpreted assuming a reactivity sequence r, as following: rH2> rC2H6 >> rC2H4 which is the opposite of the heats of adsorption Hads C2H4> Hads C2H6 >> Hads H2 as derived from independent chromatographic and spectroscopic information. This is a good example of selective zeolite catalysts with adsorption characterestics for competing molecules under conditions (OXD) which overcome the thermodynamic limitations of standard dehydrogenation reactions.Pubblicazioni consigliate
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