基于密度泛函理论的HCN与H_(2)/H_(2)O气相反应机理研究  

Study on gas phase reaction mechanism of HCN and H_(2)/H2O based on density functional theory

作　　者：孙明哲 许建良[1] 侯秋实 代正华[1,3] 王辅臣 SUN Mingzhe;XU Jianliang;HOU Qiushi;DAI Zhenghua;WANG Fuchen(School of Resources and Environmental Engineering,East China University of Science and Technology,Shanghai Coal Gasification Engineering Technology Research Center,Shanghai 200237,China;Shanghai Huanqiu Engineering Co.,Ltd,Shanghai 200032,China;School of Chemical Engineering,Xinjiang University,Urumqi 830046,China)

机构地区：[1]华东理工大学资源与环境工程学院上海市煤气化工程技术研究中心,上海200237 [2]上海寰球工程有限公司,上海200032 [3]新疆大学化工学院,新疆乌鲁木齐830046

出　　处：《燃料化学学报（中英文）》2024年第6期850-863,共14页Journal of Fuel Chemistry and Technology

基　　金：国家重点研发计划(2022YFB4101500);新疆维吾尔自治区自然科学基金重点项目(2023D01D02);上海市2021年科技创新行动计划课题(21DZ1209003)资助。

摘　　要：含HCN的废弃物在气化炉内的高温转化是其绿色处理的方法之一,其中,HCN与H_(2)/H_(2)O的反应是其在气化炉内的主要转化过程。本工作基于密度泛函理论,采用Gaussian及其配套软件对HCN与H_(2)/H_(2)O的反应机理进行了研究。通过分子成键、断键角度提出HCN与H_(2)/H_(2)O的各两种反应路径,结合能垒和热力学分析确定了相对最优路径,并计算了相对最优反应路径的速率常数。结果表明,HCN与H_(2)反应相对最优路径为:三个H_(2)分子在C=N上分三步进行加成得到产物CH4+NH_(3);HCN与H_(2)O反应相对最优路径为:H_(2)O分子进攻C原子,O原子和C原子的H先后转移至N原子得到产物CO+NH_(3)。两条相对最优路径在1473 K以上有明显反应速率,分别为9.57×10^(-4)和1.71 mol/(L·s)。研究结果为高温下HCN与H_(2)/H_(2)O反应的工艺和设备开发提供了理论数据支撑。HCN is a highly toxic substance that can enter the human body through the skin and respiratory system,and in severe cases,cause death.HCN can achieve partial conversion under high-temperature gasification conditions,mainly by reacting with H_(2) and H_(2)O.In order to further explore the micro reaction mechanism of HCN with H_(2) and H_(2)O during gasification,and to investigate the effects of temperature and pressure changes on the reaction,this paper uses quantum chemical simulation methods to study the reaction path,reaction thermodynamics,and kinetics of the above reactions,and quantitatively analyzes the changes in thermodynamic parameters and reaction rate constants with temperature,fitting the Arrhenius equation related to the reaction.Calculate the distribution of Fukui functions for various reactants and intermediates in the reaction process of HCN with H_(2) and H_(2)O using Multiwfn,and speculate on possible reaction pathways.The transition state search and single point energy calculation of the reaction process between HCN and H_(2) and H_(2)O were carried out using Gaussian&Gaussian View.Similarly,using the wave function program Multiwfn to calculate the Mayer bond order.The analysis of the bond order curve during the reaction process can reveal the changes in the strength of chemical bonds and the situation of bond formation and breaking.Use the Shermo program to calculate the thermodynamic parameters of each stagnation point at different temperatures,including enthalpy,entropy,Gibbs free energy,and partition function.Finally,the KiSThelP program was used to calculate the reaction rate constants for each step of the reaction based on classical transition state theory at different temperatures.The results show that the relatively optimal path for the reaction between HCN and H_(2) is as follows:three H_(2) molecules are added in three steps on C≡N to obtain the product CH4+NH_(3);The relatively optimal path for the reaction between HCN and H_(2)O is as follows:H_(2)O molecules attack C atoms,and th

关 键 词：HCN 气相反应 密度泛函理论 热力学 动力学 

分 类 号：O643[理学—物理化学]