木质素模化物键离解能的理论研究  

Theoretical study of bond dissociation energies for lignin model compounds

作　　者：黄金保[1] 武书彬[2] 程皓[2] 雷鸣[2] 梁嘉晋[2] 童红[1] 

机构地区：[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

出　　处：《燃料化学学报》2015年第4期429-436,共8页Journal of Fuel Chemistry and Technology

基　　金：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)

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EB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Cα-O键的平均键离解能最小,为182.7 k J/mol;其次是β-O-4连接中的Cβ-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。The bond dissociation energies （BDE） ofC -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 theo retically cal culated by using density functional the ory 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 Cα -O （182.7 kJ/mol） is the lowest, and that of Cβ-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 bet wee n C-O bond lengths and BD E.Compared with C-O bon ds, BDE of C-C bo nds are littlea ffected by the substituent on thea romatic groups, but affected obviously by the substituent on alkylg roups.There isa strong linear relationship between C-C bond lengths and BDE.The BDE are weakw hen the C-C bond lengt hs are lon g.

关 键 词：木质素模化物 键离解能 取代基 密度泛函理论 

分 类 号：TK6[动力工程及工程热物理—生物能]