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The mechanism and kinetics of the production of hydroxymethyl hydroperoxide (HMHP) in ethene/ ozone/water gas-phase system were investigated at room temperature (298±2 K) and atmospheric pressure (1×105 Pa). The reactants were monitored in situ by long path FTIR spectroscopy. Peroxides were measured by an HPLC post-column fluorescence technique after sampling with a cold trap. The rate constants (k3) of reaction CH2O2+H2O→HMHP (R3) determined by fitting model calculations to ex-perimental data range from (1.6―6.0)×10?17 cm3·molecule?1·s?1. Moreover, a theoretical study of reac-tion (R3) was performed using density functional theory at QCISD(T)/6-311+(2d,2p)//B3LYP/6-311+G(2d, 2p) level of theory. Based on the calculation of the reaction potential energy surface and intrinsic reac-tion coordinates, the classic transitional state theory (TST) derived k3 (kTST), canonical variational tran-sition state theory (CVT) derived k3 (kCVT), and the corrected kCVT with small-curvature tunneling (kCVT/SCT) were calculated using Polyrate Version 8.02 program to be 2.47×10-17, 2.47×10-17 and 5.22×10-17 cm3·molecule-1·s-1, respectively, generally in agreement with those fitted by the model.
The mechanism and kinetics of the production of hydroxymethyl hydroperoxide (HMHP) in ethene / ozone / water gas-phase system were investigated at room temperature (298 ± 2 K) and atmospheric pressure (1 × 105 Pa). The reactants were monitored in situ by long path FTIR spectroscopy. Peroxides were measured by an HPLC post-column fluorescence technique after sampling with a cold trap. The rate constants (k3) of reaction CH2O2 + H2O → HMHP (R3) determined by fitting model calculations to ex- perimental data range from (1.6-6.0) × 10-17 cm3 · molecule · 1 · s · 1. Furthermore, a theoretical study of reac- tion (R3) was performed using density functional theory at QCISD (T) / 6-311 + 2d, 2p) // B3LYP / 6-311 + G (2d, 2p) level of theory. Based on the calculation of the reaction potential energy surface and intrinsic reac tion coordinates, the classic transitional state theory (TST) derived k3 ( kTST), canonical variational tran-sition state theory (CVT) derived k3 (kCVT), and the corrected kCVT with small-curvature tun (kCVT / SCT) were calculated using Polyrate Version 8.02 program to be 2.47 × 10-17, 2.47 × 10-17 and 5.22 × 10-17 cm3 · molecule-1 · s-1, respectively, generally in agreement with those fitted by the model.