高取代度淀粉醋酸酯的合成及表征

采用活化淀粉作为原料,醋酸酐作为酯化剂,浓硫酸作为催化剂,在冰醋酸溶剂体系中合成了高取代度淀粉醋酸酯,通过正交实验探讨了各因素与取代度的关系。实验发现,淀粉活化预处理有利于高取代度淀粉醋酸酯的合成;醋酸酐用量是影响淀粉醋酸酯取代度的主要因素,反应温度和催化剂用量是次要因素;最佳反应条件:活化淀粉15.87 g,反应温度70℃,醋酸酐用量28 g,催化剂浓硫酸用量0.7 g,在此条件下制得的淀粉醋酸酯的取代度DS=2.465。通过扫描电镜对淀粉醋酸酯与淀粉的结构进行了观察,发现其聚集态与原淀粉相比发生本质改变,表面疏松多孔,比表面积增大,因此产品具有较好的溶剂溶解性能。

Synthesis and characterization of starch acetate of high degree of substitution

Using activated starch as raw materials,acetic anhydride as esterifying agent,oil of vitriol as activation catalyst to synthesize starch acetate of high degree of substitution in the solvent of acetic acid.Seeing about influence of several reaction parameters on substituting degree of starch acetate.It was found that the pretreatment of starch can promote the synthesis of the starch acetate of high degree of substitution.Amount of acetic anhydride is main factor,temperature of reaction,amount of activation catalyst are secondary factors and the best reaction condition are as follows:activated starch is 15.87 g,reaction temperature is 70℃,acetic anhydride is 28 g,oil of vitriol is 0.7 g.Under these conditions we will obtain high substitute starch acetate(DS=2.465).The structure of starch and starch acetate are scanned by SEM and it was found that the aggregation of starch acetate differs from the starch essentially,the surface is loosen and porous and the specific surface area is larger so it has excellent solubility in organic solvents.