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The insertion reaction mechanism of CBr2with CH3CHO has been studied by using the B3LYP/6-31G(d) method. The geometries of reactions, transition state and products were completely optimized. All the energy of the species was obtained at the CCSD(T)/6-31 G(d) level. All the transition state is verified by the vibrational analysis and the internal reaction coordinate (IRC) calculations. The results show that the propionaldehyde (HP1) is the main product of CH2 insertion with CH3CHO. The calculated results indicated that all the major pathways of the reaction were obtained on the singlet potential energy surface. The singlet CBr2 not only can insert the Cα-H [reaction 1(1)]) but also can react with CβH [reaction II(1)]. The statistical thermodynamics and Eyring transition state theory with Wigner correction are used to study the thermodynamic and kinetic characters of 1(1) and 11(1) in temperature range from 100 to 2200 K. The results show that the appropriate reaction temperature rang is 250 to 1750 K and 250 to 1600 K at 1.0 atm for 1(1) and 11(1) respectively. The rate constant and equilibrium constant are distinct in the range from 250 to 1000 K so that 1(1) more easily occurs, while the reactions are not selected in the temperature range of 1000-1600 K. [ABSTRACT FROM AUTHOR]

The insertion reaction mechanism of CBr2 with CH3CH2O has been studied by using the B3LYPI6-311G(d) and CCSD(T)/6-311G(d) at single point. The geometries of reactions, transition state and products were completely optimized. All the transition state is verified by the vibrational analysis and the internal reaction coordinate (IRC) calculations. The results show that reaction (1) is the dominant reaction path, which proceeds via two steps: i) two reactants form an intermediate (IM1), which is an exothermal re- action of 8.62 kJ · mol-1 without energy barrier; ii) P1 is obtained via the TS1 and the H-shift, in which the energy barrier is 44.53 kJ · mol-1. The statistical thermodynamics and Eyring transition state theory with Wigner correction are used to study the thermodynamic and kinetic characters of this reaction in temperature range from 100 to 2200 K. The results show that the appropriate reaction temperature ranges from 200 to 1900 K at 1.0 atm, in which the reaction has a bigger spontaneity capability, equilibrium constant (K) and higher rate constant (k). [ABSTRACT FROM AUTHOR]