Prediction and Control of Extent of Deploymerization of Chitosan by Hydroperoxide

过氧化氢氧化降解壳聚糖的可控性研究 Prediction and Control of Extent of Deploymerization of Chitosan by Hydroperoxide 覃彩芹 QIN Cai\|qin 1 first-author 肖玲 XIAO Ling 1 杜予民 DU Yu\|min 1 樊木 FAN Mu 1 施晓文 SHI Xiao\|wen 1 武汉大学化学与环境科学学院,武汉,430072 武汉大学化学与环境科学学院,武汉,430072 College of Chemistry and Environment Science, Wuhan University College of Chemistry and Environment Science, Wuhan University 壳聚糖能被过氧化氢氧化降解得到低分子量壳聚糖 ,所得产物分子量分布随平均分子量的下降而逐渐变窄 .其降解速度和产物特性受原料脱乙酰度、反应介质、H2 O2 用量、温度和反应时间的影响 .脱乙酰度越高的壳聚糖 ,降解反应越容易进行 .在酸性介质中的降解 ,其起始速度比在水中的降解要快 ,所得产物的分散度要小 ,到一定程度后受到 H+抑制 .实验结果表明 ,制备分子量 5万以上的壳聚糖产品在 6 0～ 70℃、H2 O2 用量比小于0 .2 5的中性体系中就可以完成 ;而制备分子量在 1.5～ 5万之间的壳聚糖 ,采用反应温度 70℃、H2 O2 用量比为 0 .5～ 1.5、介质为水的条件较适宜 ;盐酸体系有利于制备分子量 70 0 0左右的壳聚糖 ;要得到水溶性产物 ,可以使用 2 %醋酸或水两种介质 .因此 ,通过选择反应条件 ,可制备特定分子量范围的壳聚糖 . The molecular size of chitosan can be modified by depolymerization with hydroperoxide. The measurements of molecular weight distributions of products demonstrated the ability to control the reaction and produce oligomers of a preselected size.Chitosan exhibited significantly increased reactivity as the degree of deacetylation of the polymer increased. The effects of hydrogen ion, concentration of hydroperoxide, temperature and reaction time on the depolymerization were discussed respectively. Optimized degradation conditions were identified for preparation of chitosan with chosen dimensions. 壳聚糖 氧化降解 过氧化氢 可控降解 chitosan oxidative degradation hydroperoxide controllable depolymerization 10.14188/j.1671-8836.2000.02.017 O636.1 中金集团资助项目 2000-02-01 2021-04-01 2