摘要
在无催化剂条件下,以离子液体氯化一丁基三甲基咪唑(BMIMCL)为反应介质,均相合成了高取代度的蜡质玉米淀粉醋酸酯,并用FT-IR、1H NMR、SEM、XRD、TGA等方法对其进行分析.实验结果表明:淀粉醋酸酯的取代度最大能达到2.96,此时的最佳反应条件为醋酸酐与脱水葡萄糖单元摩尔比5∶1,反应温度105℃,反应时间4 h;淀粉分子的羟基上成功引入了酯化基团;在离子液体中溶解及与醋酸酐的反应过程中,淀粉的晶体结构遭到破坏,形成了新的结晶结构;淀粉醋酸酯的热稳定性优于原淀粉,并且取代度越高,热稳定性越好.
In this investigation, waxy maize starch acetates with high degree of substitution＇ （DS） were homogene- ously synthesized without any catalyst, with ionic liquid 1-butyl-3-methylimidazolium （BMIMCL） as the reaction medium. Then, the products were analyzed by means of FF-IR, 1H NMR, SEM, XRD and TGA. Experimental re- sults indicate that （ 1 ） the maximum DS is up to 2.96 in optimal conditions, namely, an molar ratio of acetic an- hydride to anhydroglucose units of 5： 1, a reaction temperature of 105 ℃ and a reaction time of 4 h; （2） the acetyl groups are introduced to the hydroxyl groups in starch products ; （3） during the dissolution of the starch in the ionic liquid and the reaction with acetic anhydride, the crystalline structure of native starch is disrupted and a new struc- ture forms; and （4） the thermal stability of starch acetates is better than that of the native starch and it increases with DS.
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2012年第8期133-138,共6页
Journal of South China University of Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(21004023)
华南理工大学中央高校基本科研业务费专项资金资助项目(2009ZM0124)
关键词
乙酰化
离子液体
玉米淀粉
醋酸酐
均相合成
催化剂
acetylation
ionic liquid
maize starch
acetic anhydride
homogeneous synthesis
catalyst
