This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with t...This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.展开更多
木质素作为自然界含量仅次于纤维素的生物质资源,其聚芳香结构具有紫外吸收特性,研究价值较高。但工业木质素因来源和提取工艺不同,相对分子质量和结构不均匀,产品性能各异。本研究采用乙醇溶液法分级纯化玉米芯工业木质素(EL 0),得到EL...木质素作为自然界含量仅次于纤维素的生物质资源,其聚芳香结构具有紫外吸收特性,研究价值较高。但工业木质素因来源和提取工艺不同,相对分子质量和结构不均匀,产品性能各异。本研究采用乙醇溶液法分级纯化玉米芯工业木质素(EL 0),得到EL100、EL 70和ELR 3种级分,再将各木质素级分分别掺入商用婴儿面霜中制备木质素基防晒霜,并评估其防晒性能。对制备所得木质素基防晒霜进行防晒性能测试可得,分级前后木质素样品的紫外吸收能力由强到弱依次为ELR> EL 70> EL 0> EL 100;当木质素基防晒霜中木质素质量分数为10%时,EL 0防晒霜的防晒系数(SPF)值仅为12.55;ELR防晒霜的SPF值达51.79,防晒性能增强,但产品颜色较深;EL 70防晒霜的SPF值为48.88,同时颜色相对较浅,应用领域更加广泛。研究结果表明,乙醇溶液法分级处理可有效降低木质素结构的非均质性,优化木质素在防晒产品中的作用效果。展开更多
文摘This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.
文摘木质素作为自然界含量仅次于纤维素的生物质资源,其聚芳香结构具有紫外吸收特性,研究价值较高。但工业木质素因来源和提取工艺不同,相对分子质量和结构不均匀,产品性能各异。本研究采用乙醇溶液法分级纯化玉米芯工业木质素(EL 0),得到EL100、EL 70和ELR 3种级分,再将各木质素级分分别掺入商用婴儿面霜中制备木质素基防晒霜,并评估其防晒性能。对制备所得木质素基防晒霜进行防晒性能测试可得,分级前后木质素样品的紫外吸收能力由强到弱依次为ELR> EL 70> EL 0> EL 100;当木质素基防晒霜中木质素质量分数为10%时,EL 0防晒霜的防晒系数(SPF)值仅为12.55;ELR防晒霜的SPF值达51.79,防晒性能增强,但产品颜色较深;EL 70防晒霜的SPF值为48.88,同时颜色相对较浅,应用领域更加广泛。研究结果表明,乙醇溶液法分级处理可有效降低木质素结构的非均质性,优化木质素在防晒产品中的作用效果。
