氨与一氧化二氮气相反应机理的理论研究

Theoretical study on the gas-phase reaction mechanism of ammonia with nitrous oxide.

作者信息

Li Yuyan, Jiang Rongpei, Xu Sen, Gong Xuedong, Pan Feng, Pang Aimin

机构信息

School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094, People's Republic of China.

Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology, Xiangyang, Hubei, 441003, People's Republic of China.

出版信息

J Mol Model. 2020 Feb 4;26(3):48. doi: 10.1007/s00894-020-4291-1.

DOI:10.1007/s00894-020-4291-1

PMID:32020355

Abstract

Applications of nitrous oxide (NO) as an oxidant in green propellants and propulsion systems have attracted a lot of attention. In this study, the reaction pathways for the oxidation of ammonia (NH) with NO were studied using the B3LYP/6-31++G** method of density functional theory (DFT). The results reveal that the reaction between NO and NH proceeds through a chain reaction mechanism. NO reacts with NH to form N and NHO first and then NHO decomposes into NH and O. This process corresponds to the apparent reaction NO+M=N+O+M (M=NH), but the energy barrier of the process (183.49 kJ/mol) is much lower than the direct decomposition reaction of NO=N+O (279.05 kJ/mol). The O radical produced in this process reacts subsequently with NH and NO to produce more radicals such as NH, OH, and NO, which will take part in further reactions like NH+OH=NH+HO and NH+NO=N+HO until the reactants are consumed.

摘要

一氧化二氮（NO）作为绿色推进剂和推进系统中的氧化剂的应用已引起了广泛关注。在本研究中，采用密度泛函理论（DFT）的B3LYP/6-31++G**方法研究了氨（NH₃）与NO氧化反应的途径。结果表明，NO与NH₃之间的反应通过链式反应机理进行。NO首先与NH₃反应生成N₂和N₂H₂O，然后N₂H₂O分解为NH₃和O。此过程对应于表观反应NO + M = N₂ + O + M（M = NH₃），但该过程的能垒（183.49 kJ/mol）远低于NO = N₂ + O的直接分解反应（279.05 kJ/mol）。此过程中产生的O自由基随后与NH₃和NO反应生成更多自由基，如NH₂、OH和NO₂，这些自由基将参与进一步的反应，如NH₂ + OH = NH₃ + H₂O和NH₂ + NO₂ = N₂ + H₂O，直到反应物被消耗。