A theoretical study on the reaction mechanisms of O(³P)+1‐butene

Abstract

ABSTRACT:The reaction of O( 3 P) with 1-butene (CH 3 CH 2 CH¼ ¼CH 2 ) are examined by applying the UMP2 and G3 methods. The minimum energy crossing points (MECPs) between the singlet and triplet potential energy surfaces are located using the Newton-Lagrange method, and it is shown that the MECPs play a key role in the reaction mechanisms. The complex reaction mechanisms are revealed for both adiabatic and nonadiabatic reaction channels, and the observations in several recent experiments can be rationalized based upon the present calculations. The calculational results indicate that the site selectivity of the addition of O( 3 P) to either carbon atom of the double bond of 1-butene is not remarkable. In addition, the formation mechanisms of butenols are discussed. The butenols can be created not only by the keto-enol tautomerization, but also by the rearrangement and decomposition reaction involving the epoxy compound.

Combined Experimental and Theoretical Studies of the O(3P) + 1-Butene Reaction Dynamics: Primary Products, Branching Fractions, and Role of Intersystem Crossing

“…A large variety of product channels are energetically allowed for the O­( 3 P) + 1-butene reaction; the main ones, which have been experimentally observed and theoretically studied in the present work, are listed below, with the reaction enthalpies as from the present work (these values refine and supersede those from previous, lower-level electronic structure calculations by Zhao et al): …”

“…27,28 A large variety of product channels are energetically allowed for the O( 3 P) + 1-butene reaction; the main ones, which have been experimentally observed and theoretically studied in the present work, are listed below, with the reaction enthalpies as from the present work (these values refine and supersede those are mainly on reaction kinetics rather than dynamics measurements. In particular, very limited previous theoretical work 38,39 on the reaction potential energy surface (PES) existed prior to the present study.…”

“…Compared to the O­( 3 P) + C 2 H 2 , C 2 H 4 , C 3 H 4 , and C 3 H 6 reactions, fewer experimental studies are available on the reaction O­( 3 P) + 1-butene, and all of them are mainly on reaction kinetics rather than dynamics measurements. In particular, very limited previous theoretical work , on the reaction potential energy surface (PES) existed prior to the present study.…”

The reliability of DFT methods to predict electronic structures and minimum energy crossing point for [FeIVO](OH)2 models: A comparison study with MCQDPT method

“…(The program can be obtained from the authors upon request.) The early version of this program has been used successfully to search the MECP of some nontransition metal reaction systems . Unfortunately, multireference perturbation theory lacks analytic gradients in GAMESS program.…”

Sequential Capture of O(3P) and HCN by Helium Nanodroplets: Infrared Spectroscopy and ab Initio Computations of the 3Σ O–HCN Complex

“…However, O­( 3 P) reactions with alkenes are predicted to cross the postulated 8.75 eV threshold as the alkene substitution pattern evolves from ethene (no substitution) to propene (methyl group substitution) to butene (dimethyl substitution, of which there are four different isomers), and this trend was tested by Sabbah et al Their findings corroborated the behavior predicted by Smith et al The HCN + O­( 3 P) results presented here demonstrate the feasibility for analogous alkene + O­( 3 P) spectroscopic studies, in which O­( 3 P) and alkenes of varying substitution are combined in helium droplets via the sequential capture scheme. As the real reaction barrier (i.e., for the ethene and propene reactions) evolves to being submerged below the asymptotic limit (i.e., for the butene reactions), one might expect that strongly bound reaction intermediates, such as triplet biradicals, ,− will be observed in helium droplets, rather than van der Waals complexes. Given the fact that a 10 000 atom helium droplet can dissipate 140 kcal/mol, it should be possible to quench the internal energy of these reaction intermediates and probe them for the first time spectroscopically.…”