分子量是聚合物的重要特性之一,木质素的分子量及其分布是研究苯丙烷类结构的反应、物理化学特性和评价其改性产物质量的内容之一。本研究以陆地棉TM-1成熟纤维为材料,分别利用酶解-温和酸解木质素法和二氧六环法提取棉纤维中木质素,结...分子量是聚合物的重要特性之一,木质素的分子量及其分布是研究苯丙烷类结构的反应、物理化学特性和评价其改性产物质量的内容之一。本研究以陆地棉TM-1成熟纤维为材料,分别利用酶解-温和酸解木质素法和二氧六环法提取棉纤维中木质素,结合凝胶渗透色谱法(gel permeation chromatography,GPC)调查和评价2种方法获得的棉纤维中木质素的相对分子量。结果表明,经二氧六环处理提取的棉花纤维中的木质素(dioxane lignin,DL)的重均分子量为2924g mol^(–1)、数均分子量2403 g mol^(–1),略高于由酶解-温和酸解处理提取的木质素(enzymatic hydrolysis-mild acidolysis lignin,EMAL)的重均分子量(2169 g mol^(–1))和数均分子量(1970 g mol^(–1)),EMAL的多分散系数稍低,说明木质素的均一性比DL高。表明EMAL法提取的木质素更适用于分析棉纤维中木质素的相对分子量。利用EMAL法分析棉纤维中木质素相对分子量表明,不同棉花品种的木质素重均分子量分布范围为938~2169 g mol^(–1),数均分子量分布范围为857~1970 g mol^(–1),多分散性系数在1.09~1.74间,均小于2。重均分子量与纤维马克隆值呈显著负相关,数均分子量与纤维长度呈显著负相关,与纤维马克隆值呈极显著负相关。展开更多
采用纤维素酶/稀酸处理法从浙江产天然毛竹中分离木质素。优化毛竹酶解的反应条件,并考察不同pH值对木质素产率的影响,确定分离木质素的最佳反应条件。最佳反应条件为:酶解反应时,控制酶/底物比1∶8,底物浓度为0.025g/mL,反应温度50℃...采用纤维素酶/稀酸处理法从浙江产天然毛竹中分离木质素。优化毛竹酶解的反应条件,并考察不同pH值对木质素产率的影响,确定分离木质素的最佳反应条件。最佳反应条件为:酶解反应时,控制酶/底物比1∶8,底物浓度为0.025g/mL,反应温度50℃下反应48h;稀酸处理时,pH值为0.82。用红外光谱(Fourier Transform Infrared Spectroscopy,FT-IR)和核磁共振氢谱(1 H Nuclear Magnetic Resonance Spectra,1 H-NMR)对优化条件下分离的精炼木质素样品进行表征分析,结果表明:精炼木质素具有典型的紫丁香基和愈创木基特征峰,而纤维素、半纤维素及碳水化合物的特征峰含量很小。精炼木质素进行了化学成分分析的结果表明:纤维素酶/稀酸处理法分离的木质素与传统的磨木木质素法相比方法相比,纯度和产率具有较大提升。展开更多
In an effort to utilize NMR technique for the analysis of the structural components of wood and biomasses such as lignin, we made a comparative study of lignin contents of several types of lignocellulosie materials bo...In an effort to utilize NMR technique for the analysis of the structural components of wood and biomasses such as lignin, we made a comparative study of lignin contents of several types of lignocellulosie materials both before and after enzymatic hydrolyses. To this end, Eucalyptus Globulus, Norway spruce thermomeehanieal pulp（TMP） corn stover and Eucalyptus kraft pulp were ball-milled and treated with cellulase to prepare materials with high lignin contents. These materials were analyzed via ^31p NMR in ionic liquids. The results show that the contents of various functional groups for the lignocellulosic materials after enzymatic hydrolyses are generally in agreement with those from their corresponding enzymatic mild acidolysis liginins（EMALs）, indicating that ^31p NMR analysis of lignocellulosic materials in ionic liquids is a promising method for quantitative characterization of lignocellulosic materials.展开更多
文摘分子量是聚合物的重要特性之一,木质素的分子量及其分布是研究苯丙烷类结构的反应、物理化学特性和评价其改性产物质量的内容之一。本研究以陆地棉TM-1成熟纤维为材料,分别利用酶解-温和酸解木质素法和二氧六环法提取棉纤维中木质素,结合凝胶渗透色谱法(gel permeation chromatography,GPC)调查和评价2种方法获得的棉纤维中木质素的相对分子量。结果表明,经二氧六环处理提取的棉花纤维中的木质素(dioxane lignin,DL)的重均分子量为2924g mol^(–1)、数均分子量2403 g mol^(–1),略高于由酶解-温和酸解处理提取的木质素(enzymatic hydrolysis-mild acidolysis lignin,EMAL)的重均分子量(2169 g mol^(–1))和数均分子量(1970 g mol^(–1)),EMAL的多分散系数稍低,说明木质素的均一性比DL高。表明EMAL法提取的木质素更适用于分析棉纤维中木质素的相对分子量。利用EMAL法分析棉纤维中木质素相对分子量表明,不同棉花品种的木质素重均分子量分布范围为938~2169 g mol^(–1),数均分子量分布范围为857~1970 g mol^(–1),多分散性系数在1.09~1.74间,均小于2。重均分子量与纤维马克隆值呈显著负相关,数均分子量与纤维长度呈显著负相关,与纤维马克隆值呈极显著负相关。
文摘采用纤维素酶/稀酸处理法从浙江产天然毛竹中分离木质素。优化毛竹酶解的反应条件,并考察不同pH值对木质素产率的影响,确定分离木质素的最佳反应条件。最佳反应条件为:酶解反应时,控制酶/底物比1∶8,底物浓度为0.025g/mL,反应温度50℃下反应48h;稀酸处理时,pH值为0.82。用红外光谱(Fourier Transform Infrared Spectroscopy,FT-IR)和核磁共振氢谱(1 H Nuclear Magnetic Resonance Spectra,1 H-NMR)对优化条件下分离的精炼木质素样品进行表征分析,结果表明:精炼木质素具有典型的紫丁香基和愈创木基特征峰,而纤维素、半纤维素及碳水化合物的特征峰含量很小。精炼木质素进行了化学成分分析的结果表明:纤维素酶/稀酸处理法分离的木质素与传统的磨木木质素法相比方法相比,纯度和产率具有较大提升。
基金Supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education, China and the Scientific and Technological Development Programs of of Beijing Municipal Education Commission (No.KM201010011004)
文摘In an effort to utilize NMR technique for the analysis of the structural components of wood and biomasses such as lignin, we made a comparative study of lignin contents of several types of lignocellulosie materials both before and after enzymatic hydrolyses. To this end, Eucalyptus Globulus, Norway spruce thermomeehanieal pulp（TMP） corn stover and Eucalyptus kraft pulp were ball-milled and treated with cellulase to prepare materials with high lignin contents. These materials were analyzed via ^31p NMR in ionic liquids. The results show that the contents of various functional groups for the lignocellulosic materials after enzymatic hydrolyses are generally in agreement with those from their corresponding enzymatic mild acidolysis liginins（EMALs）, indicating that ^31p NMR analysis of lignocellulosic materials in ionic liquids is a promising method for quantitative characterization of lignocellulosic materials.
