杜仲半纤维素乙酰化的研究

杜仲枝材经粉碎成粉后，用体积比为2：1的苯-乙醇溶液抽提，去除有机溶剂抽出物；在酸性条件下采用亚氯酸钠法分离综纤维素；在20℃用质量分数为10％的氢氧化钠处理10h，从综纤维素中提取半纤维素，用体积分数95％的乙醇沉淀析出，并用70％的乙醇洗涤半纤维素；在均相的N，N-二甲基甲酰胺（DMF）／氯化锂（LiCl）体系中，以吡啶为催化剂用乙酸酐对半纤维素进行改性．实验条件下所得的改性半纤维素的取代度在0．51～1．17之间，采用红外光谱对改性前后的半纤维素进行了表征．

Study on Acetylation of Hemicellulose from Eucommia ulmoides Oliver

The Eucommia ulmoides Oliver material was pretreated,then with the benzene-ethylalcohol extraction Eucommia powder,was removed the organic solvent to extracts. The hemicellulose were then obtained from the holocellulose by extraction with 10% sodium hydroxide for 10 h at 20 ℃ ,precipitated with 95% ethanol,and then washed by 70% ethanol. The acetylation of hemicellulose was carried out in a homogeneous N,N-dimethylformamide and lithium chloride system with acetic anhydride using pyridine as a catalyst. The degree of substitution of hemicellulose acetates ranged between 0.51 and 1.17 as a function of experimental conditions. And infrared analysis was applicated in acetylated hemicellulose.