Abstract: The influence of extraction method and structure type on the pyrolysis behavior of lignin was investigated. The functional groups and pyrolysis characteristics of Klason lignin extracted from cotton stalk and walnut shell by the Klason method (labeled as KCSL and KWSL, respectively), and milled wood lignin extracted from walnut shell via the Björkman method (labeled as BWSL), were analyzed with Fourier transform infrared spectroscopy (FTIR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). The results were compared with commercial alkali lignin (CAL). The FTIR results revealed that alkali lignin, cotton stalk lignin and walnut shell lignins were Type G, Type GS and Type HGS, respectively. The pyrolysis results from Py-GC/MS suggested that the products distribution of various lignins were affeted by material type and extraction method greatly. The contents of catechol derivatives obtained from KCSL, KWSL and BWSL were 28.18%, 18.12% and 35.11%. Meanswhile modification of BWSL was mainly attributed to the breakage of benzyl aryl ether linkages, whereas cleavage of ether bonds at the α-and β-positions on the propanoid side chain was the marked feature of Klason lignin.

Key words: lignin, structure analysis, fast pyrolysis, pyrolysis behavior

摘要： 为研究结构类型和提取方法对木质素热解特性的影响，本研究采用Klason方法预处理得到的棉杆、核桃壳Klason木质素和贝克曼方法预处理得到的核桃壳磨木木质素（MWL），并结合傅里叶红外光谱仪（FT-IR）和快速热解仪-气相色谱/质谱联用（Py-GC/MS）对其化学结构和热解特性进行分析。FT-IR表明碱木质素为G型木质素，棉杆木质素属于GS类型木质素，而核桃壳木质素具有 HGS木质素的特征；Py-GC/MS分析发现原料的变化以及提取方法对木质素热解产物的组成有明显的影响，在棉杆Klason木质素中邻苯二酚类产物含量为28.18%，而在核桃壳Klason和磨木木质素的含量分别为18.12%和35.11%。同时研究表明经两种方法处理的木质素结构有明显的不同，其中Klason木质素结构中苯丙酸侧链上的α-和β-醚键明显断裂，而贝克曼处理主要体现在苯基芳基醚键的断裂。

关键词: 木质素, 结构分析, 快速热解, 热裂解特性