β-O-4型木质素二聚体模型化合物热解机理及产物选择性理论

发布时间：2018-08-02 08:45

【摘要】：木质素作为含量仅次于纤维素的天然可再生资源,将其转化为高附加值的平台化合物具有重大的经济以及环境意义。本文针对具有β-O-4典型连接方式的木质素二聚体模型化合物[2-甲氧基(2′-甲基-2′-苯基乙基)苯醚],利用密度泛函理论方法 B3LYP,在6-31G(d,p)基组水平上对其热解反应机理以及产物形成选择性进行理论研究,分析了二聚体中各化学键的解离能及Mulliken布居数,设计并计算了8条后续可能反应路径的标准热力学参数。研究结果表明,该木质素二聚体模型化合物的初次热裂解路径主要为C_β—O键均裂的反应;热解的主要产物是酚类化合物如苯、苯酚、邻苯二酚以及烃类化合物如烯烃等;其中路径1是热力学支持的最优路径,其能垒为44.73k J/mol。
[Abstract]:Lignin, as a natural renewable resource only inferior to cellulose, is of great economic and environmental significance to convert it into a high value-added platform compound. In this paper, the [2- methoxy (2 '- methyl -2' - phenyl ethyl) phenyl ether, a lignin two polymer model compound with a typical connection of beta -O-4, is used in density functional theory. On the basis of method B3LYP, the mechanism of pyrolysis reaction and the selectivity of product formation were studied at the level of 6-31G (D, P) base group. The dissociation energy of the chemical bonds and the number of Mulliken populations in the two polymer were analyzed. The standard thermodynamic parameters of the 8 subsequent possible reaction paths were designed and calculated. The results showed that the two polymer model of the lignin was found. The primary pyrolysis path of the compound is mainly the reaction of C_ beta O bond, and the main pyrolysis products are phenols such as benzene, phenol, catechol and alkenes such as alkenes, and path 1 is the optimal path for thermodynamic support, and its energy barrier is 44.73k J/mol.
【作者单位】：华南农业大学食品学院;
【基金】：国家自然科学基金(21576107) 广东省科技计划(2014A010106024)项目
【分类号】：O636.2

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