以小麦淀粉为原料,氯乙酸作为醚化剂,采用2次加碱法制备了高取代度的羧甲基小麦淀粉.以4.05 g淀粉为基准,采用正交试验对反应条件进行优化,探讨了水含量、乙醇用量、醚化温度对产品取代度的影响.结果表明,其制备的最佳工艺条件为:水用量6 mL,无水乙醇用量60 mL-氯乙酸与淀粉物质的量比为1.4,氢氧化钠与氯乙酸物质的量比为1.8,碱化用氧氧化钠质量分数70％,碱化温度35～40℃,碱化时间0.5 ～1 h,醚化温度50～55℃,醚化时间2～3h,在此条件下制得了取代度(DS)高达1.21的羧甲基小麦淀粉.并采用红外光谱和XRD对产物结构进行了表征.%Carboxymethyl wheat starch (CMHS) with high degree of substitution (DS) was synthesized from wheat starch with chloroacetic acid as the etherifying agent by twice alkalifying method. The process conditions were optimized by orthogonal experiment using 4. 05 g of starch as the criterion, and the effects of water content, ethanol amount and etherification temperature on the DS of CMHS were investigated. The results indicated that the optimal process conditions were as follows; water content 6 mL, absolute ethyl alcohol 60 mL, molar ratio of chloroacetic acid to starch 1.4, molar ratio of sodium hydroxide to chloroacetic acid 1. 8 , mass fraction of sodium hydroxide 70% (for alkalization) , alkalization temperature 35 - 40 ℃ , alkalization time 0. 5 - 1 h, etherification temperature 50 - 55 ℃ and etherification time 2-3 h,and CMHS with DS up to 1.21 was obtained under this synthetic conditions. Moreover, the product structure was characterized by FT-IR and XRD.
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