The adsorption and the mechanism of the oxidative dehydrogenation (ODP) of propane over VO2-exchanged 14T MCM-22 and 12T ZSM-5 zeolites were investigated by density functional theory calculations at the M06-L/6-31G(d,p) level of theory. The adsorption energies of propane are comparable to the ones derived from computationally much more demanding MP2 calculations and to experimental results while, as expected, the values from the B3LYP functional are too small. The reaction begins with the abstraction of a methylene hydrogen to the oxygen atom of VO2 group, leading to a HO-V-O intermediate. This step is the rate determining step with apparent activation energies of 30.9 and 32.3 kcal/mol for MCM-22 and ZSM-5, respectively. The subsequent step is the propene together with the water formation. Although the catalyst reoxidation step was not included in rate limiting step, it was found to be important for releasing the product at the end of the reaction.

DFT study of oxidative dehydrogenation of propane over a VO<sub>2</sub>-exchanged MCM-22 and ZSM-5 zeolites

240th National Meeting (2010)

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DFT study of oxidative dehydrogenation of propane over a VO2-exchanged MCM-22 and ZSM-5 zeolites

DFT study of oxidative dehydrogenation of propane over a VO₂-exchanged MCM-22 and ZSM-5 zeolites