| Summary: | 碩士 === 國立交通大學 === 應用化學系碩博士班 === 99 === A diaphramless shock tube coupled with atomic resonance absorption spectrophotometry (ARAS) was employed to study the kinetics of the reactions of triplet methylene with oxygen and hydrogen between 1800 and 2000 K.
We obtained Ln ( k3-2 / cm3 molecule-1 s-1 ) = - ( 17.28 ± 0.79 ) - ( 30.17 ± 1.40 ) × 103 / T , the second step rate constants of the CH2I2 thermal decomposition , in this temperature range . This is the first experimental result reported on the CH2I2 thermal decomposition.
For the reaction 3CH2 + H2 , Ln ( k3-8 / cm3 molecule-1 s-1 ) = - ( 22.0 ± 1.9 ) - ( 7.8 ± 3.7 ) × 103 / T was yielded in this study. Present experimental results are found to be consistent with the calculations from our previous work of 0.48 ppm CH3OH + 1000 ppm H2 thermal decomposition. We also determined the rate constants for CH3 + H2 reaction , Ln ( k3-9 / cm3 molecule-1 s-1 ) = - ( 16.8 ± 2.4 ) - ( 21.0 ± 4.7 ) × 103 / T , which agrees with previous references. k3-12 (T) = (2.84 ± 0.12) × 10-11 exp[-(755 ± 33)/T) cm3 molecule-1 s-1 is the total rate constant for 3CH2 +O2 determined in this study. Our results agree with that of Vinckier and Debruyn when extrapolation at high temperature. k3-12 (T) = (2.2 + 1.1/-0.8 ) × 10-11 exp[(-1.5 ± 0.3) kcal mol-1/RT] that predicted by Vinckier與Debruyn. After combining the result of this work and Moore et al. the branching fractions for this reaction were obtained as follow : CO + OH + H channel : 0.3，CO2 + 2H channel :?n0.15，CH2O + O channel :?n0.3，CO2 + H2 channel : 0.25 .
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