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

马弗炉CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2017年第36卷第12期

·4436· 化工进

大胡子小展

樊荻，解新安，李璐，李雁，黎巍，魏星，孙娇

（华南农业大学食品学院，广东广州 510642）

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44.73kJ/mol 。

关键词：木质素；β-O-4型二聚体；密度泛函理论；热解机理；产物选择性

中图分类号：X7 文献标志码：A 文章编号：1000–6613（2017）12–4436–09

DOI ：10.16085/j.issn.1000-6613.2017-0553

Theoretical study on pyrolysis and product selectivity of β-O-4 type lignin

dimer model

F AN Di ，XIE Xin’an ，LI Lu ，LI Yan ，LI Wei ，WEI Xing ，SUN Jiao

（College of Food Science ，South China Agricultural University ，Guangzhou 510642，Guangdong ，China ） Abstract: Lignin ，as the second most available cellulose in botanic field ，it is of great economic and environmental significance to convert it into targeted platform compounds. To understand the pyrolysis mechanism of lignin ，the 1-methoxy-2-(2-phenylpropoxy) benzene was selected as a lignin dimer model compound of β-O-4-linkage. The pyrolysis of this dimer was investigated using density functional theory B3LYP methods at 6-31G （d ，p ）level. Eight possible pyrolysis pathways (mainly the homolytic cleavage of C —O bond) were proposed according to bond dissociation energies of lignin dimer model ，then the activation energies for each reaction pathway were calculated. The calculation results showed that the bond dissociation energy of C β—O was the lowest ，and that of O —CH 3 the second lowest. The order of all kinds of bond dissociation energy is C β—O ＜O —CH 3＜C α—C β＜C α—C γ＜C aromatic —O ＜C α—C aromatic ＜C aromatic —OCH 3. It could be deduced that the dimer was mainly decomposed through the cleavage of the C β—O linkage. And major pyrolytic products of phenol and alkene compounds were formed in this process ．Thus ，the optimum pathway1 can be determined based on its thermodynamic parameters and lowest energy barrier of 44.73kJ/mol.

Key words ：lignin ；β-O-4 linkage dimer ；density functional theory ；pyrolysis mechanism ；product selectivity黄金龟甲虫

胶体金法

淮海医药网第一作者：樊荻（1992—），女，硕士研究生。联系人：解新安，研究员，研究方向为化工系统建模、模拟与优化研究。E-mail ：xinanxie@scau.edu 。收稿日期：2017-03-30；修改稿日期：2017-04-28。

基金项目：国家自然科学基金（21576107）及广东省科技计划湖南确诊h5n6

（2014A010106024）项目。

本文发布于:2024-09-23 22:32:30，感谢您对本站的认可！

本文链接：https://www.17tex.com/xueshu/502842.html

上一篇：脱硝SCR区热解炉电加热器控制方案优化及应用

下一篇：硫酸锰热解制备三氧化二锰以及用热解尾气浸出低品位软锰矿的实验研究