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采用D -近似最优设计法系统地研究了NaOH质量分数、碱处理时间及碱处理温度这三个主要因素对制备壳聚糖的影响 :当碱液质量分数增加时 ,壳聚糖的脱乙酰度增加 ,但其速度却在减小 ,当碱液质量分数达到 40 %时 ,脱乙酰度出现峰值 ,约为 90 % ,而后增加碱液质量分数时 ,脱乙酰度反而下降 ;随着反应温度的升高 ,其脱乙酰度几乎线性递增 ,当温度达到 2 0 0℃附近时 ,曲线趋于平直并且脱乙酰度达到最大 ;随着反应时间的增加 ,脱乙酰度开始呈线性增加 ,当反应时间超过 5 0min后 ,脱乙酰度有下降趋势 ;在一定碱液质量分数 (4 0 % )条件下 ,脱乙酰度随着温度的增加而增加 ,因此 ,若需获得较高质量的壳聚糖 ,必须提高反应温度
The effects of NaOH concentration, alkali treatment time and alkali treatment temperature on the preparation of chitosan were studied systematically using D - approximate optimal design method. When the mass fraction of lye increased, the deacetylation of chitosan Degree of increase, but its speed is decreasing. When the mass fraction of lye reaches 40%, the degree of deacetylation peak, about 90%, and then increase the lye mass fraction, the degree of deacetylation decreases; with the reaction temperature The degree of deacetylation increases almost linearly. When the temperature reaches around 200 ℃, the curve tends to be straight and the degree of deacetylation reaches the maximum. With the increase of reaction time, the degree of deacetylation begins to increase linearly. When the degree of deacetylation increases linearly, When the reaction time exceeds 50 min, the degree of deacetylation tends to decrease. At a certain lye mass fraction (40%), the degree of deacetylation increases with the increase of temperature. Therefore, if a higher quality of chitosan Sugar, you must increase the reaction temperature