A QUANTUM-CHEMICAL STUDY OF HYDRIDE TRANSFER IN CATALYTIC TRANSFORMATIONS OF PARAFFINS ON ZEOLITES - PATHWAYS THROUGH ADSORBED NONCLASSICALCARBONIUM-IONS

A quantum-chemical investigation of the hydride transfer reaction in c atalytic transformations of hydrocarbons on zeolites has been performe d. Ab initio calculations at the MP2/6-31++G*//HF/6-31G* level demons trated that the activated complexes of hydride transfer reaction in ca talytic transformations of paraffins on zeolites very much resemble ad sorbed nonclassical carbonium ions. However, these transient species a re strongly held at the surface active sites by the Coulomb interactio n. The calculated activation energies for reactions involving propane and isobutane are in a reasonable agreement with the experimental data .