α-O-4型木质素二聚体裂解机理的研究  

Theoretical study on pyrolysis process of α-O-4 type lignin dimer model

作　　者：罗海银 田红[1] 唐世斌[1] 熊家佳 

机构地区：[1]长沙理工大学能源与动力工程学院,长沙410004

出　　处：《兰州大学学报（自然科学版）》2016年第2期271-276,共6页Journal of Lanzhou University(Natural Sciences)

基　　金：国家自然科学基金项目(51276023);国家自然科学基金国际(地区)合作与交流项目(51310105026);湖南省重点实验室开放基金项目(2014ZNDL006)

摘　　要：以α-O-4型木质素二聚体为研究对象,以密度泛函理论B3LYP/6-31G（d,p）为基础,对该木质素二聚体的裂解反应过程进行了分子动力学模拟研究.提出了5种可能的热解反应途径,对各种反应的反应物、产物、中间体和过渡态的结构进行了能量梯度全优化.计算了各热解反应途径的标准动力学参数,分析了主要热解产物的形成演化机理.结果表明：在木质素二聚体的初反应中,R4和R5的反应焓变较小,分别为1.65×10^5、1.36×10^5J/mol,因此C_a-O和C_4-O键也较易断裂.通过计算次反应路径的势垒,发现R4-3和R5-3反应的势垒较小,因此在该裂解过程中会优先选择R4-3和R5-3路径.该反应路径最后得到的产物有苯、苯酚、邻苯二酚、对甲基苯甲醚、甲烷,与实验结果一致.Density functional theory B3LYP/6-31G（d,p） was used to study reaction mechanism of molecular structure of α-O-4 type lignin dimers compound based on quantum chemistry.Five possible pyrolytic pathways were proposed and the equilibrium geometries of the reactants transition states,intermediate and products were fully optimized.The standard kinetic parameters in each reaction pathway were calculated and the formation and evolution mechanism of main pyrolysis products were analyzed.The results shows that the enthalpy of R4 and R5 in the original reaction of lignin model compound is 1.65× 10^5 and 1.36×10^5 J/mol,respectively.So C_α-O keys and C_4-O key is easy to break.By calculating the reaction path barrier,R4-3 and R5-3 reaction barriers are small;it will choose the R4-3 and R5-3 path in the pyrolysis process.Products of the reaction path finally obtained benzene,phenol,catechol,p-methyl anisole,methane,which agrees with the experiment result.

关 键 词：α-O-4型木质素二聚体 密度泛函理论 裂解机理 分子动力学模拟 

分 类 号：TK62[动力工程及工程热物理—生物能] O636.2[理学—高分子化学]