Studies of the reaction processes of atmospheric minor constituents related to the global warming

用绝对速率法和相对速率法研究了2952K时氯原子与环己酮在6托或800-950托氮气中的反应活性。绝对速率实验得到k(氯+环己酮)=(1.88±0.38)×10^&lt；-10&gt；相对速率实验得到k(氯+环己酮)=(1.66±026)×10^&lt；-10&gt；cm^3分子^&lt；-1&gt；S^&lt；-1&gt；环己酮在285 nm附近有一个宽的紫外光吸收带，最大吸收截面为(4.0±03)×10~(-20)cm~2分子^~(-1)~(-1)~(gt；)。在295±2K下，用绝对(PLP-LIF)和相对速率技术研究了氯+CH3(CH2)3CHO反应的动力学和机理。绝对速率实验得到8吨Ar中k(C_1+CH_3(CH_2)_3CHO)=(2.31±0.35)×10~(-10)；相对速率实验得到k(CI+CH_3(CH_2)_3CHO)=(2.24±0.20)×10~(-1)；-10&gt；cm^3分子^~(-1)；S^~(-1)~(-1)；在800~950吨N_2中，额外的相对速率实验得到…。700吨N_2中k(Cl+CH_3(CH_2)_3C(O)CI)=(8.74±1.38)×10~(-1)×10~(-1)cm~(-1)·cm~(-3)分子^~(-1)~(-1)~(-1)S。烟雾室傅里叶变换红外光谱(F-IR)分析表明，酰基生成通道占反应的42±3%。利用脉冲激光光解真空紫外激光诱导荧光(PLP-LIF)技术研究了氯原子与丙酮、丁酮、2-戊酮、3-己酮、2-己酮、3-己酮和环戊酮在295±2K下的气相反应。在351 nm处由Cl2光解产生了CL(^2P3/2)原子，并在134.72 nm处用激光诱导荧光光谱(3p^52P3/^2-3p^44s^2/2跃迁)进行了监测。氯原子与丙酮、丁酮、2-戊酮、3-戊酮、2-己酮、3-己酮和环戊酮的反应速率系数分别为：(2.30±0.12)×10-12，(4.08±0.21)×10^&lt；-11，(1.23±013)-10^&lt；-10&gt；，(8.87s-0.92)40^&lt；-1&gt；1，(2.08±0.32)×10^&lt；-10&gt；，(1.43±0.19)×10^&lt；-10；和(1.16±0.12)×10^；-10&gt；cm^3分子^-1&gt；S^-1&gt；丙酮和丁酮的结果与以前的研究一致。2-戊酮、3-戊酮、2-己酮和3-己酮的结果比以前的绝对率研究结果高出约2-3倍。对这些差异的可能解释进行了讨论。对酮与氯原子反应的对流层寿命进行了估算和讨论。较少

Absolute and relative rate techniques were used to study the reactivity of Cl atoms with cyclohexanone in 6 Torr of argon or 800-950 Torr of N2 at 295 2 K The absolute rate experiments gave k(Cl+cyclohexanone) = (1.88 0.38)×10^<-10> while the relative rate experiments gave k(Cl+cyclohexanone) = (1.66±026)×10^<-10> cm^3 molecule^<-1> s^<-1> methods. Cyclohexanone has a broad UV absorption band with a maximum cross section of (4.0±03)×10^-20 cm^2 molecule^<-1> near 285 nm The results are discussed with respect to the literature data.The kinetics and mechanism of the reaction Cl + CH_3 (CH_2)_3CHO was investigated using absolute (PLP-LIF) and relative rate techniques in 8 Ton of argon or 800-950 Ton of N_2 at 295± 2K. The absolute rate experiments gave k(C1 + CH_3(CH_2)_3CHO) = (2.31±0.35)×10^<-10> in 8 Ton of argon while relative rate experiments gave k(CI + CH_3(CH_2)_3CHO) = (2.24±0.20)×10^<-10> cm^3 molecule^<-1> s^<-1> in 800-950 Ton of N_2. Additional relative rate experiments gave … More k(Cl+CH_3(CH_2)_3C(O)CI) = (8.74± 1.38)×10^<-11> cm^3 molecule^<-1> s^<-1> in 700 Ton of N_2. Smog chamber Fourier transform infrared (F IR) techniques indicated that the acyl-forming channel accounts for 42 ± 3% of the reaction. The results are discussed with respect to the literature data and the importance of long range (= 2 carbon atoms along the aliphatic chain) effects in determining the reactivity of organic molecules towards chlorine atoms.The gas-phase reactions of Cl atoms with acetone, butanone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, and cyclopentanone at 295±2 K were studied using pulsed laser photolysis vacuum UV laser-induced fluorescence (PLP-LIF) techniques. Cl(^2P_3/_2) atoms were produced by photolysis of Cl_2 at 351 nm and monitored by LIF spectroscopy at 134.72 nm (3p^5 2P_3/^2-3p^44s ^2_3/2 transition). Rate coefficients for reactions of Cl atoms with acetone, butanone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, and cyclopentanone are : (2.30±0.12)×10_-12, (4.08±0.21)×10^<-11>, (1.23±013)-〜10^<-10>, (8.87s-0.92)40^<-1>1, (2.08±0.32)×10^<-10>, (1.43±0.19)×10^<-10> and (1.16±0.12)×10^<-10> cm^3 molecule^<-1>s^<-1>, respectively. The results for acetone and butanone are consistent with previous studies. The results for 2-pentanone, 3-pentanone, 2-hexanone, and 3-hexanone are approximately a factor of 2-3 higher than those from previous absolute rate studies. Likely explanations for these discrepancies are discussed. Tropospheric lifetimes of ketones with respect to reaction with Cl atoms are estimated and discussed. Less