摘要
通过对不同催化剂、催化剂量、反应温度和反应时间等反应条件下得到的改性木质素与甲醛反应活性的研究,确定了木质素脱甲基化反应条件,并通过FT-IR半定量、GPC1、H NMR对木质素脱甲基化前后结构进行表征。FT-IR半定量表明木质素甲氧基由反应前的0.990降至0.765,酚羟基由1.174增至1.529;GPC表明木质素脱甲基化后大分子木质素发生了降解,分子量小于2000的木质素含量由由改性前的38%增至改性后的51%;1H NMR表明木质素改性后脂肪族侧链与苯环分离,同时大量-βO-4醚键裂解。
Optimal lignin demethylation conditions were determined through demethylated lignin reactive activity toward formaldehyde, in terms of variation of catalyst, amount of catalyst, reaction temperature and reaction time. Lignin and its demethylated derivate product were characterized by semiquantitative FT-IR, GPC, and a H NMR. Results demonstrate that the content of methoxy group decreases from 0. 990 to 0. 765, and the content of phenolic hydroxyl group increases from 1. 174 to 1. 529 via semiquantitative FT-IR. GPC results indicate that macromolecular lignin degrades after demethylation,the content of Mwbelow 2000 dramatically increases from 38% to 51%. 1H NMR shows that alkyl chain breaks from benzene ring and β-O-4 linkages cleave and almost disappear after demethylateion.
出处
《高分子通报》
CAS
CSCD
北大核心
2012年第3期77-84,共8页
Polymer Bulletin
基金
林业公益性行业科研专项(201104004)
林业科学技术推广项目([2010]05)
关键词
木质素
脱甲基化
反应活性
结构表征题
Lignin
Demethylation
Reactive activity
Structural characterization
