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以壳聚糖(CTS)和氯乙酸为原料,合成了羧甲基壳聚糖(CMC)。采用红外光谱(FTIR)、核磁共振氢谱(1HNMR)、环境扫描电镜(ESEM)和X-射线衍射(XRD)对其结构进行了表征。考察了氯乙酸用量、碱液浓度、碱化时间和反应温度对其O-位取代度(Y_1)和N-位取代度(Y_2)的影响。并在单因素实验的基础上,利用响应面法Box-Behnken实验设计原理中的BBD数学模型,优化了壳聚糖羧甲基化的工艺参数。结果显示:制备羧甲基壳聚糖的最佳工艺条件为,氯乙酸用量5.71 g、w(NaOH)=54%、碱化时间7 h、反应温度40℃。在此工艺条件下,得到产物的Y_1=0.721 3,Y_2=0.285 7,与回归模型的预测结果很接近,相对误差值为0.22%和0.27%。
Chitosan (CTS) and chloroacetic acid as raw materials, the synthesis of carboxymethyl chitosan (CMC). Its structure was characterized by FTIR, 1HNMR, ESEM and XRD. The effects of the amount of chloroacetic acid, the concentration of lye, the alkalization time and the reaction temperature on the degree of substitution (Y_1) and degree of substitution (Y_2) of O-substitution were investigated. On the basis of single factor experiment, BBD mathematic model in response to Box-Behnken experimental design principle was used to optimize the process parameters of carboxymethylation of chitosan. The results showed that the optimum conditions for the preparation of carboxymethyl chitosan were as follows: the amount of chloroacetic acid was 5.71 g, w (NaOH) = 54%, the alkalization time was 7 h and the reaction temperature was 40 ℃. Under these conditions, Y_1 = 0.721 3 and Y_2 = 0.285 7 were obtained, which were close to the regression model predictions. The relative error values were 0.22% and 0.27% respectively.