Ab initio study of the unimolecular decomposition of 2‐butenenitrile: Molecular elimination channels

Abstract

AbstractAb initio molecular orbital calculations have been performed for the unimolecular decomposition of 2‐butenenitrile (CH3CHCHCN), especially for HCN and H2 molecular elimination channels. Structures and energies of the reactants, products, and relevant species in the individual reaction pathways were determined by MP2 gradient optimization and MP4 CCSD(T) single‐point energy calculations. Direct 1,1 and 1,2 molecular eliminations and H or CN migration followed by elimination channels were identified. Dissociation rates for the individual reaction pathways were calculated from vibrational frequencies at the ab initio transition state geometries by employing Rice–Ramsperger–Kassel–Marcus theory, from which channel branching ratios were determined. It was concluded that the most important reaction channel should be the direct 1,1 three‐center molecular elimination of HCN. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007