用硫酸法提取农作物废弃物稻草中的木质素,采用质量分数72%的硫酸,以15(mg)∶1(L)的液固单位比,室温下反应2 h,得到产率9.23%的木质素.利用扫描电镜(SEM)、综合热分析、傅里叶红外光谱(FTIR)和氢核磁共振波谱(1H-NMR)分析手段表征木质素的物理性质和化学结构,结果表明:木质素呈表面粗糙且有大量孔隙的不规则块状结构,在175~700 ℃内发生热解,分子结构中存在着大量羟基、羰基和醚键等活性官能团,属于对羟基苯基-愈创木基-紫丁香基型木质素.
In this work,lignin was extracted from rice straw by sulfuric acid.The brown lignin was obtained through extraction by 72% H2SO4 for 2 h at room temperature and the ratio of liquid to solid was 15.The content of lignin in rice straw was 9.23%.The lignin was analyzed using scanning electron microscope(SEM),thermogravimetric analysis and differential scanning calorimetry(TG-DSC),Fourier transform infrared spectroscopy(FT-IR)and proton nuclear magnetic resonance(1H-NMR).It was showen that the lignin was irregular block,its surface was rough and lacunaris,and it had a good thermal stability,and the decomposition temperature of lignin was between 175 ℃ and 700 ℃.It contained many functional groups like hydroxyl,carbonyl,ether linkage and benzene ring structure and was composed of p-hydroxyphenyl lignin,guaiacyl lignin and syringyl lignin.
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