Feng Yuan, Zhu Jizhen, Wang Sixu, Yu Liang, He Zhuoyao, Qian Yong, Lu Xingcai
Key Laboratory for Power Machinery and Engineering of M. O. E, Shanghai Jiao Tong University, 200240 Shanghai, P. R. China.
J Phys Chem A. 2021 Jul 15;125(27):5976-5989. doi: 10.1021/acs.jpca.1c02713. Epub 2021 Jul 2.
3-Pentanol is a potential alternative fuel or a green fuel additive for modern engines. The H-abstraction reactions from 3-pentanol by H, CH, HO, and OH radicals are significant in the 3-pentanol oxidation process. However, corresponding rate constants are forced to rely on either analogy from -butanol or estimation from alkanes due to a lack of direct experimental and theoretical study. In this work, stationary points on the potential energy surfaces (PESs) were calculated with the high-level DLPNO-CCSD(T)/CBS(T-Q)//M06-2X/cc-pVTZ method, which is further used to benchmark against the CBS-QB3 method. Then, the high-pressure limit rate constants for target reactions, over a broad range of temperature (400-2000 K), were calculated with the phase-space theory and conventional transition state theory. A comparison was made between the calculated rate constants and the values available in Carbonnier et al. [ 2019, 37(1), 477-484]. The rate constants for the above H-abstraction reactions in the Carbonnier model were updated with the calculated results, followed by a modification based on the computed results of 3-pentanol + HO to obtain the revised model. Validation against the shock tube (ST) and the jet-stirred reactor (JSR) measurements from the literature proved the revised model an optimal one. Furthermore, using an ST, ignition delay times (IDTs) for the 3-pentanol/air mixtures were measured spanning a temperature range of 920-1450 K, pressures of 6, 10, and 20 bar, and equivalence ratios of 0.5, 1.0, and 1.5. Generally, IDTs decrease with increasing temperature and reflected shock pressure. Improved predictions to present experimental data were obtained by using the revised model as compared with the Carbonnier model. Finally, sensitivity analysis was conducted using the revised model to gain an in-depth comprehension of the 3-pentanol autoignition.
3-戊醇是现代发动机潜在的替代燃料或绿色燃料添加剂。在3-戊醇氧化过程中，H、CH、HO和OH自由基从3-戊醇中夺取氢的反应非常重要。然而，由于缺乏直接的实验和理论研究，相应的速率常数不得不依赖于与丁醇的类比或烷烃的估算。在这项工作中，使用高水平的DLPNO-CCSD(T)/CBS(T-Q)//M06-2X/cc-pVTZ方法计算了势能面（PESs）上的驻点，并进一步用于与CBS-QB3方法进行基准测试。然后，利用相空间理论和传统过渡态理论，计算了目标反应在较宽温度范围（400-2000K）内的高压极限速率常数。将计算得到的速率常数与Carbonnier等人[2019, 37(1), 477-484]中的可用值进行了比较。用计算结果更新了Carbonnier模型中上述夺氢反应的速率常数，并根据3-戊醇+HO的计算结果进行修正，得到修正模型。与文献中的激波管（ST）和喷射搅拌反应器（JSR）测量结果进行对比验证，证明修正模型是最优的。此外，使用激波管测量了3-戊醇/空气混合物在920-1450K温度范围、6、10和20bar压力以及0.5、1.0和1.5当量比下的点火延迟时间（IDTs）。一般来说，点火延迟时间随温度和反射激波压力的增加而减小。与Carbonnier模型相比，使用修正模型对当前实验数据有了更好的预测。最后，使用修正模型进行了敏感性分析，以深入了解3-戊醇的自燃情况。
