摘要
由于淀粉是一种多晶高聚物,其颗粒中一部分分子排列成疏松的非晶区,另一部分分子则排列成高度有序的结晶区,磷酸盐不易深入到颗粒内部,反应往往只能发生在颗粒表面,导致淀粉反应活性和反应效率较低,难以得到高取代度的产物。今利用自制的搅拌球磨机将普通木薯淀粉进行机械活化预处理,正磷酸盐为酯化剂,尿素为催化剂,干法制备淀粉磷酸酯。探讨了活化时间、磷酸盐用量、pH值、反应温度、反应时间和尿素用量对取代度(DS)和反应效率(RE)的影响,确定了最佳反应条件:活化时间1.5h,磷酸盐用量12%,pH4.5,反应温度150℃,反应时间2h,尿素用量2%。研究结果表明:机械活化预处理方法能显著提高木薯淀粉磷酸酯的DS和RE,表明机械活化能有效地提高木薯淀粉的化学反应活性。最佳工艺条件下木薯淀粉磷酸酯的DS和RE为0.0900和0.933。
Starch is a morphologically complex polymer substance which consists of loose amorphous regions interspersing with highly regular crystalline regions, therefore it is difficult for the phosphate to contact with the inner molecules of the starch, which will result in low starch activity, low reaction efficiency and producing starch phosphate with low degree substitution （DS） for the esterification reaction of the starch. In this work, the starch phosphate was synthesized by dry process, during which, a customized stirring-type ball mill was used to mechanically activate the cassava starch, the orthophosphate and the urea were used separately as esterifying agent and as catalyst. The effects of activation time, reaction temperature and time, the amount of urea and phosphate used and the pH value on the degree of substitution and reaction efficiency （RE） were investigated. The suitable reaction conditions were obtained as follows： activation time of 1.5 h, amount of phosphate of 12%, pH value of 4.5, reaction temperature of 150~C, reaction time of 2 h and amount of urea of 2%. The results indicate that the mechanical activation considerably enhances the chemical reactivity of the starch, and hence promotes the DS and RE of the cassava starch phosphate. Using above suitable reaction conditions, the DS and RE of the starch phosphate prepared can reach 0.0900 and 0.933, respectively.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2009年第3期491-495,共5页
Journal of Chemical Engineering of Chinese Universities
基金
广西高校研究生创新基金(2006081702M20)
关键词
木薯淀粉
机械活化
淀粉磷酸酯
干法
cassava starch
mechanical activation
starch phosphate
dry process
作者简介
作者简介：田保华（1982-）-女，山东滨州人,广西大学硕士生。
通讯联系人：童张法，E-mail： bioche@gxu.edu.cn
