Temperature-Dependence of the Rates of Reaction of Trifluoroacetic Acid with Criegee Intermediates
Temperature-Dependence of the Rates of Reaction of Trifluoroacetic Acid with Criegee Intermediates
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三氟乙酸与 Criegee 中间体的反应速率的温度依赖性
DOI：
10.1002/ange.201703700
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发表时间：
2017
影响因子：
--
通讯作者：
Chhantyal-Pun R
中科院分区：
文献类型：
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作者：
Chhantyal-Pun R
三氟乙酸（TFA）与两种Criegee中间体（甲醛氧化物和丙酮氧化物）的气相反应的速率系数在240-340 K范围内随着温度的升高而降低。 294 K时的速率系数k（CH 2 OO + CF 3COOH）=（3.4±0.3）×10− 10 cm 3s − 1和k（（CH 3）2COO + CF 3COOH）=（6.1±0.2）×10− 10 cm 3s − 1超过了碰撞极限值的估计值，表明由于两种反应物的大永久偶极矩，捕获机制提高了速率。 观察到的温度依赖性归因于预反应复合物的竞争稳定。将该复合物的形成过程拟合到一个模型中，得到CH 2 OO + CF 3COOH和（CH 3）2COO + CF 3COOH反应的k [cm 3s −1]=（3.8±2.6）×10− 18 T2 exp（（1620±180）/T）+ 2.5×10− 10和k [cm 3s −1]=（4.9±4.1）×10− 18 T2 exp（（1620±230）/T）+ 5.2×10− 10。探讨了与生物Criegee中间体反应从大气中去除TFA的后果。
The rate coefficients for gas‐phase reaction of trifluoroacetic acid (TFA) with two Criegee intermediates, formaldehyde oxide and acetone oxide, decrease with increasing temperature in the range 240–340 K. The rate coefficients k(CH2OO + CF3COOH)=(3.4±0.3)×10−10cm3s−1and k((CH3)2COO + CF3COOH)=(6.1±0.2)×10−10cm3s−1at 294 K exceed estimates for collision‐limited values, suggesting rate enhancement by capture mechanisms because of the large permanent dipole moments of the two reactants. The observed temperature dependence is attributed to competitive stabilization of a pre‐reactive complex. Fits to a model incorporating this complex formation give k [cm3s−1]=(3.8±2.6)×10−18T2exp((1620±180)/T) + 2.5×10−10and k [cm3s−1]=(4.9±4.1)×10−18T2exp((1620±230)/T) + 5.2×10−10for the CH2OO + CF3COOH and (CH3)2COO + CF3COOH reactions, respectively. The consequences are explored for removal of TFA from the atmosphere by reaction with biogenic Criegee intermediates.