Li Sijie, Dames Enoch, Davidson David F, Hanson Ronald K
Department of Mechanical Engineering, Stanford University , Stanford, California 94305, United States.
J Phys Chem A. 2014 Jan 9;118(1):70-7. doi: 10.1021/jp411141w. Epub 2013 Dec 19.
The overall rate constants of hydroxyl radicals (OH) with ethylamine (EA: CH3CH2NH2) and dimethylamine (DMA: CH3NHCH3) were investigated behind reflected shock waves using UV laser absorption of OH radicals near 306.7 nm. tert-Butyl hydroperoxide (TBHP) was used as the fast source of OH at elevated temperatures. Test gas mixtures of individual amines and TBHP, diluted in argon, were shock-heated to temperatures from 901 to 1368 K at pressures near 1.2 atm. The overall rate constants were determined by fitting the measured OH time-histories with the computed profiles using a detailed mechanism developed by Lucassen et al. (Combust. Flame 2012, 159, 2254-2279). Over the temperature range studied, the measured rate constants can be expressed as kEA+OH = 1.10 × 10(7)·T(1.93) exp(1450/T) cm(3) mol(-1) s(-1), and kDMA+OH = 2.26 × 10(4)·T(2.69) exp(1797/T) cm(3) mol(-1) s(-1). Detailed error analyses were performed to estimate the overall uncertainties of the measured reaction rate constants, and the estimated (2σ) uncertainties were found to be ±31% at 901 K and ±22% at 1368 K for kEA+OH, and ±29% at 925 K and ±21% at 1307 K for kDMA+OH. Variational transition state theory was used to compute the H-abstraction rates by OH for ethylamine and dimethylamine, with the potential energy surface, geometries, frequencies, and electronic energies calculated by Galano and Alvarez-Idaboy (J. Chem. Theory Comput. 2008, 4, 322-327) at CCSD(T)/6-311++G(2d,2p) level of theory. The calculated reaction rate constants are in good agreement with the experimental data.
利用306.7nm附近OH自由基的紫外激光吸收，在反射激波后研究了羟基自由基（OH）与乙胺（EA：CH3CH2NH2）和二甲胺（DMA：CH3NHCH3）的总包反应速率常数。叔丁基过氧化氢（TBHP）在高温下用作OH的快速来源。将单独胺类与TBHP的测试气体混合物在氩气中稀释，在接近1.2atm的压力下激波加热至901至1368K的温度。通过使用Lucassen等人开发的详细机理（Combust. Flame 2012, 159, 2254 - 2279）将测量的OH时间历程与计算的曲线进行拟合来确定总包反应速率常数。在所研究的温度范围内，测量的速率常数可表示为kEA+OH = 1.10×10(7)·T(1.93) exp(1450/T) cm(3) mol(-1) s(-1)，以及kDMA+OH = 2.26×10(4)·T(2.69) exp(1797/T) cm(3) mol(-1) s(-1)。进行了详细的误差分析以估计测量反应速率常数的总不确定度，发现对于kEA+OH，在901K时估计的（2σ）不确定度为±31%，在1368K时为±22%，对于kDMA+OH，在925K时为±29%，在1307K时为±21%。变分过渡态理论用于计算OH对乙胺和二甲胺的氢提取速率，其势能面、几何结构、频率和电子能量由Galano和Alvarez - Idaboy（J. Chem. Theory Comput. 2008, 4, 322 - 327）在CCSD(T)/6 - 311++G(2d,2p)理论水平下计算。计算得到的反应速率常数与实验数据吻合良好。
