醋酸酯化淀粉制备工艺优化

Optimization of preparation process of acetate esterified starch

以木薯淀粉为原料,醋酸酐为酯化剂,制备醋酸酯化淀粉。以取代度为指标,在单因素试验的基础上通过正交试验优化醋酸酯化淀粉制备工艺,并研究催化剂N,N-羰基二咪唑(CDI)及过硫酸钾(KPS)对取代度的影响。结果表明:最佳工艺为pH 8.5、醋酸酐添加量10%(以淀粉干基质量计)、反应时间2.0 h、反应温度30℃,在此条件下醋酸酯化淀粉取代度为0.0994;当CDI添加量4%(以淀粉干基质量计)、反应0.5 h时,取代度最高达0.1202;CDI与KPS同时添加时,取代度没有进一步提高。

Acetate esterified starch was prepared using tapioca starch as raw material and acetic an⁃hydride as esterifying agent.Using the degree of substitution as an indicator,the preparation process of acetate esterified starch was optimized through orthogonal experiments based on a single factor experi⁃ment,and the effects of catalysts N,N⁃carbonyldiimidazole(CDI)and potassium persulfate(KPS)on the degree of substitution were studied.The results showed that the optimal process was pH 8.5,acetic anhydride addition 10%(based on the dry mass of starch),reaction time 2.0 h,and reaction tempera⁃ture 30℃.Under these conditions,the degree of substitution of acetate esterified starch was 0.0994.When the addition of CDI was 4%(based on the dry mass of starch)and the reaction time was 0.5 h,the degree of substitution reached as high as 0.1202.When CDI and KPS were added simultaneously,the degree of substitution did not further improve.