Kinetic isotope effects in the gas phase reactions of OH and Cl with CH3Cl, CD3Cl, and 13CH3Cl

[摘要] The kinetic isotope effects in the reactions of CH₃Cl,¹³CH₃Cl and CD₃Cl with OH radicals and Cl atoms were studiedin relative rate experiments at 298±2 K and 1013±10 mbar. Thereactions were carried out in a smog chamber using long path FTIR detectionand the spectroscopic data analyzed employing a non-linear least squaresspectral fitting method using measured high-resolution infrared spectra aswell as absorption cross sections from the HITRAN database. The reactionrates of ¹³CH₃Cl and CD₃Cl with OH and Cl were determinedrelative to CH₃Cl as: k_OH+CH3Clk_OH+CH3Cl/k_OH+13CH3Cl}k_OH+13CH3Cl=1.059±0.008,k_OH+CH3Clk_OH+CH3Cl/k_OH+CD3Clk_OH+CD3Cl=3.9±0.4, k_Cl+CH3Clk_Cl+CH3Cl/k_Cl+13CH3Clk_Cl+13CH3Cl=1.070±0.010and k_Cl+CH3Clk_Cl+CH3Cl/k_Cl+CD3Clk_Cl+CD3Cl=4.91±0.07. The uncertainties given are 2σ from thestatistical analyses and do not include possible systematic errors. Theunexpectedly large ¹³C kinetic isotope effect in the OH reaction ofCH₃Cl has important implications for the global emission inventory ofCH₃Cl.

[学科分类] 大气科学