Density functional theory calculations of the transition states for hydrogen exchange and dehydrogenation of methane by a Brönsted zeolitic proton

D. functional and semiempirical (MNDO) theories are used to det. transition states and the corresponding activation barriers of hydrogen exchange and dehydrogenation of methane catalyzed by a protonated zeolite cluster model. The nonlocal d. functional activation barriers were found to be 125 and 343 kJ/mol for hydrogen exchange and dehydrogenation, resp. From the imaginary frequency of one of the transition state Eigen modes, the reaction coordinates were deduced. Addnl., from the activation barrier and vibration, rotation, and translation partition functions, reaction rate consts. have been evaluated using transition state reaction rate theory. [on SciFinder (R)]