摘要
为了综合利用造纸黑液,分别采用H2SO4溶液和H3PO4溶液从黑液中沉淀粗木质素,并分别用苯-乙醇溶液和丙酮溶液对其抽提纯化.考察了采用不同酸沉淀及溶剂抽提对木质素得率的影响,并对黑液木质素进行了元素分析、傅里叶红外光谱分析、13C NMR以及1H NMR等结构表征.实验结果表明:采用不同酸沉淀及溶剂抽提得到的木质素结构相差不大,采用H2SO4沉淀及苯-乙醇抽提方法制备的苯-乙醇木质素得率最高;黑液木质素含有较多的愈创木酚-紫丁香酚单元结构,呈现明显的硬木木质素特征;在苯-乙醇木质素与丙酮木质素中,苯丙烷结构单元经验式分别为C9H12.61O1.1(OCH3)1.43和C9H13.33O2.10(OCH3)1.38,每个C9单元中的β—O—4键仅为0.28和0.27个,β—β键仅为0.15和0.11个;黑液木质素中羟基和羧基数量较磨木木质素丰富.黑液木质素具备多种活性官能团,表现出与磨木木质素不同的结构特征,应用前景广阔.
To utilize the black liquor effectively, crude lignin was precipitated with H2SO4 and H3PO4, and then extracted with benzene-ethanol and acetone for purification, respectively. Effects of different acids and solvents on lignin yield were studied, and the structural characteristics of black liquor lignin were examined by elemental analysis, Fourier transform infrared spectroscopy （FFIR）, carbon-13 nuclear magnetic resonance（ 13C NMR）and proton nuclear magnetic resonance（1^H NMR） spectroscopy. The results show that lignins prepared by different methods present no difference on structure, and benzene-ethanol-extracted lignin which is precipitated by H2 SOn and purified with benzene-ethanol gives the highest yield. The lignin presents a guaiacol-syringol structure characteristics assigned to hardwood. The chemical formula of phenyl propane units are estimated to be C9H12.61 Or. t （ OCH3 ） 1.43 for benzene-ethanol-extracted lignin and C9 Hl3.33 02. 10 （ OCH3 ） 1.38 for acetone-extracted lignin. The benzene-ethanol-extracted lignin and acetone-extracted lignin elucidate β-O-4 bonds as 0. 28 and 0.27 and β-β bonds as 0. 15 and 0.11 per C9 units, respectively. Moreover, the content of hydroxyl groups and carboxyl groups of black-liquor lignin was greater. Black-liquor lignin with various functionality groups presents an active chemical structure over milled wood lignin, exhibiting its potential utilization as an important feedstock.
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2013年第1期120-124,共5页
Journal of Southeast University：Natural Science Edition
基金
江苏省高校自然科学基金资助项目(12KJB480005)
中国科学院可再生能源与天然气水合物重点试验室开放基金资助项目
关键词
黑液
木质素
分离
结构
black liquor
lignin
isolation
structure
