乙醛氧化生成乙酸反应机理的分子模拟  

Molecular Simulation on the Reaction Mechanism of Acetaldehyde Oxidization to Acetic Acid

作　　者：夏垒 龙军[1] 武志强[1] 赵毅[1] 代振宇[1] 王立华[1] XIA Lei;LONG Jun;WU Zhiqiang;ZHAO Yi;DAI Zhenyu;WANG Lihua(Research Institute of Petroleum Processing,SINOPEC,Beijing 100083,China)

机构地区：[1]中国石化石油化工科学研究院,北京100083

出　　处：《石油学报（石油加工）》2019年第1期20-27,共8页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家重点研发计划项目(2017YFB0306800)基金资助

摘　　要：采用基于密度泛函理论(DFT)的量子化学方法研究了乙醛氧化生成乙酸的反应过程。结果表明:无氧条件下链引发过程最难发生,反应能垒达到380.78kJ/mol,但氧气可将此过程的反应能垒降至116.26kJ/mol;乙酰基自由基生成过氧乙酸以及链终止反应的各步骤的反应能垒均较低,反应较快;过氧乙酸转化为乙酸的反应较难发生,为整体反应过程的速率控制环节。此过程有2个可能的反应路径,速率控制步骤分别为过氧乙酸均裂生成乙酸自由基和羟基自由基的过程及过氧乙酸与乙醛反应生成乙醛单过氧乙酸酯中间化合物的过程,反应能垒分别为147.18、137.21kJ/mol。Density functional theory(DFT)simulation method was applied to study the oxidization process of acetaldehyde to acetic acid.Simulation results suggest that,chain initiation step should be the most difficult step under anaerobic condition with a reaction energy barrier 380.78 kJ/mol.However,with the presence of oxygen,the reaction energy barrier could be decreased to116.26 kJ/mol.It has been found that reaction energy barriers in each step of acetyl free radicals reacting to peracetic acid are quite low,and also in chain termination step.It is also noticed that the reaction of peracetic acid to acetic acid is difficult to take place,and it should be the rate control step in the overall reaction process.There are two possible reaction paths in the process.The reaction rate control steps could be homolytic cleavage of peracetic acid to generate acetic acid free radical and hydroxyl free radical,or the reaction of acetaldehyde with peracetic acid to produce acetaldehyde monooxyacetate.The reaction energy barriers of the above two reactions are 147.18 kJ/mol and 137.21 kJ/mol,respectively.

关 键 词：分子模拟 氧化 醛 羧酸 

分 类 号：TE626[石油与天然气工程—油气加工工程]