A QUANTUM-CHEMICAL STUDY OF ADSORBED NONCLASSICAL CARBONIUM-IONS AS ACTIVE INTERMEDIATES IN CATALYTIC TRANSFORMATIONS OF PARAFFINS .1. PROTOLYTIC CRACKING OF ETHANE ON HIGH-SILICA ZEOLITES
Vb. Kazansky et al., A QUANTUM-CHEMICAL STUDY OF ADSORBED NONCLASSICAL CARBONIUM-IONS AS ACTIVE INTERMEDIATES IN CATALYTIC TRANSFORMATIONS OF PARAFFINS .1. PROTOLYTIC CRACKING OF ETHANE ON HIGH-SILICA ZEOLITES, Catalysis letters, 27(3-4), 1994, pp. 345-354
Ab initio quantum-chemical calculations of protolytic cracking of etha
ne on Bronsted acid sites of high silica zeolites demonstrated the con
certed mechanism of this reaction. The reaction coordinate represents
the stretching of the O-H bond in combination with heterolytic splitti
ng of the C-C ethane bond. This results in formation of methane and ad
sorption of the methyl group on the surface basic oxygen of the active
site. The geometry of such activated complex is different from that o
f adsorbed carbonium ions which also represent highly excited surface
complexes.