부산대학교 도서관

Among the elementary reactions forming the methonal and ethanol oxidation subsystem, the reactions of hydroxyalkyl radicals with O2are very important. Therefore direct discharge flow reactor measurements for CH2OH+O2Rxn. (1M) and CH3CHOH+O2Rxn. (1E) were carried out in the temperature range between 300 and 682 K at pressures around 1 mb. Radical profiles were obtained by monitoring the CH2OH and CH3CHOH radicals with a low electron energy mass spectrometer. The measured rate coefficients were corrected for kinetic interferences. Both reactions exhibit a strong non-Arrhenius behaviour. For 300≤T ≤682 K the rate coefficients can be fitted by the analytical expressions: k1M=2.5*10−9T−1+4.0*10−10exp (−2525/T) cm3/s, k1E=1.4*10−8T−1.2+8.0*10−10exp (−2525/T) cm3/s. Within our experimental accuracy no kinetic isotope effect for CH2OH/CH2OD+O2and CH3CHOH/CH3CHOD+O2was found. As a function of the ionization energy of the radical, the room temperature rate coefficients for both reactions fit the general data for alkyl +O2reactions. The reactions CH2OH+O, Rxn. (2M) and CH3CHOH+O, Rxn. (2E) have been measured directly for the first time. After application of kinetic corrections the result is k2M=(1.5±0.5)*10−10cm3/s for CH2OH+O and K2E=(1.5±0.5)*10−10*10−10cm3/s for CH3CHOH+O at ambient temperature.