玉米秸秆木质素的超临界提取及结构表征

采用超临界CO2/乙醇-水三元体系反应提取玉米秸秆中的木质素,并采用沉淀法对提取液中的木质素进行回收,得到木质素产品.利用气相色谱-质谱联用、红外光谱、紫外光谱分析了提取液成分及提取木质素产品的结构特性.采用热重分析方法对提取木质素的热稳定性进行了研究.结果表明:本试验方法提取的玉米秸秆木质素具有木质素的典型结构.提取木质素主要在180 ～500℃温度范围内分解失重.原木质素在超临界提取反应过程中发生了相当程度的降解,醚键发生了较大程度的断裂,木质素-水化合物复合体发生了不完全降解,提取木质素中含有一定量的碳水化合物.

Supercritical Extraction and Characterization of Corn Stover Lignin

ScCO2/ethanol-water was used to extract lignin from corn stover.Lignin product was obtained from the extraction by precipitation.The composition of the extract and the structure of the extracted lignin product were analyzed using GC-MS,FTIR and UV.Thermogravimetric analysis was conducted to study the thermal stability of extracted lignin.The results showed that the extracted lignin appeared to show the typical lignin structures and to decompose mostly between 180 ℃ and 500 ℃.The three dimension supramolecular structure of lignin was greatly broken down,primarily through the cleavage of ether linkages.The internal bonds of lignin-hemicellulose were not hydrolyzed completely,which leading to the extracted lignin containing a certain amount of carbohydrate.