Optimum yield of the purely heterogeneous oxidative dimerization of methane
The optimal C2-yield per pass for the purely heterogeneous catalytic oxidation of methane by O2 on Sm2O3 under continuous cofeed operation: ηopt ≤ 0.22 ± 0.03, is computed from actual kinetic data for all the pseudoelementary chemical reactions involved. The optimization dispenses with adjustable ki...
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| Autores principales: | , |
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| Formato: | JOUR |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00219517_v169_n1_p301_Colussi |
| Aporte de: |
| Sumario: | The optimal C2-yield per pass for the purely heterogeneous catalytic oxidation of methane by O2 on Sm2O3 under continuous cofeed operation: ηopt ≤ 0.22 ± 0.03, is computed from actual kinetic data for all the pseudoelementary chemical reactions involved. The optimization dispenses with adjustable kinetic parameters, and explores the combined effects of CH4 and O2 flow rates, catalyst mass, residence time, and temperature variations on the objective function η = methane conversion x C2-selectivity for the scheme: CH4 (+O2) ⇒ CH3 (→) 1/2C2H6 ⇒ 1/2C2H4 ⇒ CO. The fact that the derived ηopt value essentially coincides with the largest C2-yields reported on a myriad catalysts under vastly different conditions: (1) proves that the ceiling to selectivity is solely determined by the competition among heterogeneous processes and (2) implies a substrate-independent selectivity pattern for the species formed in O2 dissociative chemisorption. We briefly analyze the physical basis of these propositions and of the prospects of improving C2-yields beyond 25%. © 1997 Academic Press. |
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