微波法制备壳聚糖研究

采用微波炉加热，在敞口容器中，进行甲壳素脱乙酰反应，制备壳聚糖。考察了碱溶液浓度和微波加热时间对壳聚糖脱乙酰度的影响。固定微波加热时间30min，随NaOH溶液浓度增加，脱乙酰度先增加，后减小；NaOH溶液浓度为45％时，壳聚糖的脱乙酰度最高。固定NaOH溶液浓度为45％，随着微波加热时间延长，壳聚糖的脱乙酰度增加。微波加热的最佳时间为30min。加热时间继续延长，壳聚糖变黑。碱溶液浓度和微波加热时间对壳聚糖的粘均分子量影响都不大。本文试图从微波场的能量分布和微波加热机理方面解释实验结果。

Study on the Preparation of Chitosan by Microwave Irradiation

The heterogeneous deacetylation of chitin in alkaline solution under microwave irradiation in opening container was studied in this paper. The concentration of alkaline solutions and radiation time were the key factors to decide the deaeetylation of chitosan. At the fixed radiation time, the degree of deaeetylation first increased and then decreased with the increasing of the concentration of alkaline solution, and had a maximum value as the concentration being 45%. At the fixed concentration of alkaline solutions, the degree of deaeetylation rose with the irradiation time. The optimal irradiation time was 30min, in order to avoid ehitosan darking. Both the concentration of alkaline solution and the irradiation time had little effect on the viscosity - average molecular weight of chitosan. This paper aimed to analyze the experiment in terms of the energy distribution in the microwave field and the mechanisms of microwave heating.