摘要
筛选出对壳聚糖溶解具有良好性能的磺酸型离子液体[MIMBS]HSO4,以该离子液体水溶液为反应介质,在均相体系中进行了壳聚糖的氧化降解反应。考察了离子液体用量、H2O2与壳聚糖单元摩尔比、反应温度和反应时间对该氧化降解反应的影响。利用黏度法测定壳聚糖的相对分子质量,采用X射线衍射和红外光谱对原料和再生壳聚糖的结构进行表征。X射线衍射分析结果表明,溶解过程中壳聚糖的晶体结构遭到破坏,结晶度下降。随着离子液体溶液浓度的增加、H2O2用量的增大、反应温度的升高以及反应时间的延长,氧化降解反应进行得更加彻底。在最佳反应条件(8%离子液体水溶液、底物摩尔比5、反应温度80℃、反应时间3 h)下,再生壳聚糖的收率为74%,其黏均相对分子质量为21.2×103。
In this paper, ionic liquid 1-(4-sulfonic acid)butyl-3-methylimidazolium hydrogen sulfate([MIMBS] HSO4)with better dissolution performance was selected. The oxidative degradation of high molecularweight chitosan was conducted with H2O2in the above-mentioned ionic liquid aqueous solution, and the reaction system was homogeneous. In order to optimize the reaction conditions, the influence of dosage of ionic liquid, n(H2O2)∶ n(chitosan), reaction temperature and reaction time on the degradation were studied. The molecular weight of chitosan was determined by viscosity method. The structures of original and degraded chitosan were characterized by FT-IR and XRD. The results indicate that the crystal structures of chitosan are destroyed, and the crystallinity decreases. The oxidative degradation reactions proceed more completely with increasing ionic liquid concentration. At the meantime, the increased dosage of H2O2, enhanced reaction temperature and prolonged reaction time also promote this degradation reaction. The optimum conditions are determined as follows: the aqueous solution of 8%[ MIMBS] HSO4, n(H2O2)∶ n(chitosan)= 5∶1, reaction temperature equal to 80℃ and reaction time equal to 3 h. Under the above reaction conditions, the yield of the regenerated chitosan is 74%, and the viscosity-average molecular weight is 21.2× 103.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2014年第4期75-79,共5页
Polymer Materials Science & Engineering
基金
天津市自然科学基金资助项目(11JCZDJC21300)
国家自然科学基金资助项目(21346001)
关键词
酸性离子液体
壳聚糖
氧化降解
H2O2
黏度法
acidic ionic liquid
chitosan
oxidative degradation
H2O2
viscosity method
