木材类Klason法木质素的结构表征及其热解特性

Structure characterization and pyrolysis behaviour of Klason lignin from wood

运用元素分析与红外光谱分析仪（ FTIR）对Klason法提取的枫木及杉木木质素进行化学结构表征，发现枫木木质素比杉木木质素含有更多的紫丁香酚结构单元。利用热重红外联用分析仪（ TG-FTIR）研究了2种木材木质素在动态升温条件下的失重特性及主要气体产物的析出过程，发现木质素热解过程主要分2个阶段，其中枫木木质素为148～268℃及295～494℃两个阶段，杉木木质素则为150～308℃及312～518℃两个阶段。第1个阶段的主要产物是酚类化合物及二氧化碳（ CO2），第2个阶段则主要是甲烷以及甲醇的析出，一氧化碳（ CO）的生成量也有所增加。基于实验分析，采用一级一阶模型计算枫木、杉木木质素热解2个阶段的动力学参数。

The chemical structure of maple lignin and fir lignin extracted by the Klason method is characterized by the elemental analysis and the Fourier transform infrared spectroscopy （ FTIR） .It is found that lignin from maple contains more syringyl-type groups than that from fir.TG-FTIR （ ther-mogravimetric analyzer coupled with FTIR） is used to examine the characteristics of mass loss and the evolution of typical gaseous product during the dynamic heating process.Pyrolysis of the two lig-nins can be divided into two consecutive mass-loss stages：148 to 268 ℃and 295 to 494 ℃for ma-ple lignin, and 150 to 308 ℃and 312 to 518 ℃for fir lignin, respectively.Phenolic compounds to-gether with carbon dioxid （ CO2 ） are remarkably generated in the first mass-loss stage.While in the second stage, the evolutions of methane and methanol are mainly generated, and carbon monoxide （ CO） is also increased.Based on experimental analyses, a simple one-stage first-order kinetic mod-el is proposed to calculate pyrolysis kinetic parameters of two main pyrolysis stages for maple lignin and fir lignin.