乙酸基+O_(2)及其分解异构化反应速率常数计算和不确定度分析  

Calculation of Rate Constant of Addition Reaction Between O_(2)and CH_(2)CO(O)H(Including Decomposition and Isomerization)and Uncertainty Analysis

作　　者：殷阁媛 肖波 胡二江[1] 黄佐华[1] YIN Geyuan;XIAO Bo;HU Erjiang;HUANG Zuohua(State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,西安710049

出　　处：《西安交通大学学报》2023年第5期109-117,共9页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(52106182);内燃机燃烧学国家重点实验室开放课题资助项目(k2021-02);能源清洁利用国家重点实验室开放课题资助项目(ZJUCEU2021016)。

摘　　要：为了构建准确乙酸燃烧化学反应动力学模型,进行了乙酸基与O_(2)及其分解异构化高精度的量子计算。利用CCSD(T)-F12/cc-pVTZ-F12//B2PLYPD3/cc-pVTZ算法,得到了反应体系势能面,并基于多参考态方法CASPT2/CBS//CASPT2/cc-pVTZ,获得无势垒反应势能面。通过气相单分子反应理论(RRKM)和主方程理论求解了温度和压力相关的速率常数,利用可变反应坐标过渡态理论求解无势垒反应乙酸基与O_(2)加成反应的速率常数。结果表明:在低压或者高温条件下,超过99%的化学活化的O_(2)CH_(2)CO_(2)H自由基直接分解为CH_(2)O_(2)H+CO_(2)。随着压力升高,化学活化的O_(2)CH_(2)CO_(2)H碰撞稳定后生成O_(2)CH_(2)CO_(2)H,O_(2)CH_(2)CO_(2)H则在后续反应中分解为CH_(2)O_(2)H+CO_(2)。乙酸自由基在分解时,CO_(2)+CH_(3)产物通道占据主导地位。基于计算结果改进了原有乙酸模型,改进后的模型能够更好地预测层流燃烧速度,并且乙酸基存在更多的消耗路径,与量化计算结果一致。In order to develop an accurate chemical reaction kinetic model for acetic acid,high-precision quantum computation is carried out on the addition reaction between O_(2)and acetic acid radical(CH_(2)CO(O)H),and the thermal decomposition and isomerization reactions of CH_(2)CO(O)H.The potential energy surface is obtained as per the CCSD(T)-F12/cc-pVTZ-F12//B2PLYPD3/cc-pVTZ level of theory while the barrierless reaction potential energy surface using the multi-reference method CASPT2/CBS//CASPT2/cc-pVTZ.The temperature-and pressure-dependent rate coefficients are determined as per the RRKM/ME theory and the rate constant of the barrierless addition reaction between O_(2)and acetic acid radical is obtained as per the variable reaction coordinate-transition state theory.The results show that at a low pressure or high temperature,more than 99%of chemically activated O_(2)CH_(2)CO_(2)H decomposes directly into CH_(2)O_(2)H+CO_(2).With the increase of pressure,more chemically activated O_(2)CH_(2)CO_(2)H is collisionally stabilized and subsequently decomposes into CH_(2)O_(2)H+CO_(2).Moreover,CO_(2)+CH_(3)are dominant product channel of CH_(2)CO(O)H decomposition.A previous model for acetic acid is modified based on the calculation results.The improved model can better predict the laminar burning velocity and provides more pathways for CH_(2)CO(O)H consumption.The results obtained are consistent with those from quantum calculation.

关 键 词：酸雨 乙酸 无势垒反应 主方程理论 

分 类 号：V231.21[航空宇航科学与技术—航空宇航推进理论与工程]