Theoretical Studies On The Reaction Acetone With Halogen And Methyl Radical

Due to small molecule radicals with ultra-short life and high activity, together with the limitation of the existing experimental equipment, laboratory chemists can only do research of some reaction mechanism in a low-temperature range. The small molecule free radical gas phase reaction mechanism of micro-theoretical research can seek to control harmful substances to generate a major factor in reaction. provide an important theoretical basis for atmospheric environmental protection measures.By using quantum mechanics program Gaussian 03, using ab initio, with greater precision-group analyze microscopic kinetics mechanism between the presence of free radicals in the atmosphere, the activity of atoms and small molecules. In theory we can predict all possible channels and the potential of the relevant information under the atmospheric conditions. Theoretical calculation of the rate constants obtained data compared with the experimental results, which verifies the reliability of theoretical calculation.In this thesis, the mechanism of the reactions of F, Cl, Br with acetone in atmosphere has been studied with the MC-QCISD//MP2/6-31+G(d,p) level. the mechanism of the reactions of CH3 with acetone in atmosphere has been studied with the BMC-CCSD//MP2/6-31+G(d,p) level.We optimized and analyzed the geometry of the reactants, complexes, products and transition states. Under the MP2/6-31+G(d,p) level, we set the transition state as the starting point, through the minimum energy path (MEP) was obtained by intrinsic reaction coordinate (IRC) theory analyzed the electronic electrostatic potential. Further potential energy surface of single-point energy correction are in the MC-QCISD and BMC-CCSD level completed.For F, Cl and Br radicals reaction with acetone, calculated three possible reaction channels separately, the potential energy surface information obtained through the reaction energy barrier analysis, the results show that the reaction channel of H abstraction is the major channel of three channels and others are minor channels. Obtain the rate constant by theoretical calculation of reaction Cl, Br with acetone, and further confirmed that the reaction channel of H abstraction is the major channel of three channels and the other are minor channels and obtain the reaction of Br with acetone branching ratio information .To the reaction of Cl and Br with acetones, with the atomic layers increases, reaction rate constant decreases. For the methyl radical CH3 reaction with acetone, calculated two possible reaction channels, identified by calculating the hydrogen extraction reaction channel is the main reaction channel. The other channel is minor.