木质素模化物键离解能的理论研究

黄金保; 武书彬; 程皓; 雷鸣; 梁嘉晋; 童红

木质素模化物键离解能的理论研究

1.
贵州民族大学理学院, 贵州贵阳 550025;
2.
华南理工大学制浆造纸工程国家重点实验室, 广东广州 510640

基金项目: 国家自然科学基金(51266002);国家重点基础研究发展规划("973"计划,2013CB228101);贵州省教育厅自然科学研究招标项目(黔教科研发[2013]405号)。

详细信息

通讯作者:
黄金保, E-mail:huangjinbao76@126.com。

中图分类号: TK6
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出版历程
- 收稿日期: 2015-01-12
- 刊出日期: 2015-04-30

Theoretical study of bond dissociation energies for lignin model compounds

1.
School of Science, Guizhou Minzu University, Guiyang 550025, China;
2.
State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China

摘要

摘要: 采用密度泛函理论B3P86方法,在6-31G(d,p)基组水平上,对木质素结构中的6种连接方式(β-O-4、α-O-4、4-O-5、β-1、α-1、5-5)的63个木质素模化物的醚键(C-O)和C-C键的键离解能E_B进行了理论计算研究。分析了不同取代基对键离解能的影响以及键长与键离解能的相关性。计算结果表明,C-O键的键离解能通常比C-C键的小,在各种醚键中C_α-O键的平均键离解能最小,为182.7 kJ/mol;其次是β-O-4连接中的C_β-O键,苯环和烷烃基上的取代基对醚键的键离解能有较强的弱化作用,C-O键的键长和键离解能的相关性较差。与C-O键相比,C-C键的键离解能受苯环上取代基的影响很小,而烷烃基上的取代基对C-C键的键离解能有较大的影响,C-C键的键离解能和键长之间存在较强的线性关系,C-C键的键长越长,其键离解能越小。
- 木质素模化物 /
- 键离解能 /
- 取代基 /
- 密度泛函理论
Abstract: The bond dissociation energies (BDE) of C-O and C-C bond in 63 lignin model compounds for six prevalent linkages (β-O-4, α-O-4, 4-O-5, β-1, α-1 and 5-5) were theoretically calculated by using density functional theory methods B3P86 at 6-31G(d,p) level. The effect of various substituents on BDE and the correlation between the bond lengths and the corresponding BDE were analyzed. The calculation results show that C-O bond is generally weaker than C-C bond, and the average bond dissociation energy of C_α-O (182.7 kJ/mol) is the lowest, and that of C_β-O is second lowest. The substituent group on both the aromatic and alkyl groups can substantially weaken C-O bonds, and C-O bonds do not exhibit such a strong correlation between C-O bond lengths and BDE. Compared with C-O bonds, BDE of C-C bonds are little affected by the substituent on the aromatic groups, but affected obviously by the substituent on alkyl groups. There is a strong linear relationship between C-C bond lengths and BDE. The BDE are weak when the C-C bond lengths are long.
- lignin model compounds /
- bond dissociation energies /
- substituent group /
- density functional theory

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