Gas-phase and liquid-phase ozonolysis of butadiene: Theoretical investigation

A quantum chemical modeling of butadiene ozonolysis primary stage was perfomed. DFT methods, which are double-hybrid B2PLYP with basis sets aug-cc-pVDZ and aug-cc-pVTZ allowed to calculate kinetic and thermodynamic parameters in gaseous and liquid phases. The bimolecular addition reaction can proceed through different transition states - concerted and nonconcerted mechanisms. The estimation of rate constant was done in terms of the transition state theory. The polarized continuum method and the solvent model based on electron density (SMD) were utilized to take into account the effect of solvents H₂O and CCl₄. Rate constants for two different paths of addition (the Criegee and DeMore mechanisms) were estimated taking into account different configuration of the transition states. As the results show, the increase in polarity of the media leads to reaction rate increase, both by the Criegee and DeMore mechanisms. Moreover the DeMore mechanism rate constant increases in a greater extent.