O-羟丙基-N-烷基壳聚糖合成的理论研究

Theorical study on synthesis of O-hydroxypropyl-N-methyl chitosan

设计O-羟丙基-N-烷基壳聚糖合成路线,采用密度泛函理论的B3LYP/6-311+G(d,p)方法,对相关物种进行分子结构优化,所得构型均为稳定构型.对各阶段反应物分子的NBO电荷分布、键级进行模拟计算,讨论了分子的反应活性和反应位点.对各阶段反应物分子的前线轨道(FMO)进行模拟计算,分析计算结果,预测了实际反应可能发生的位点.本文研究结果为两亲性壳聚糖改性提供了一定的理论参考价值.

The rout for synthesis of O-hydroxypropyl-N-methyl chitosan was designed.Utilizing B3LYP method at the level of6-311+G(d,p),the molecular geometries of related species were optimized,and all the molecular geometries were validated to be stable.Based on the optimized geometry,the natural population analysis,the Wiberg bond indexes of reactants in each stage have been calculated with the density functional theory(DFT).According to the calculation results of the natural population analysis,the Wiberg bond indexes,the chemical reactivities and reaction sites were mainly discussed.The highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)have been calculated,too.According to concisely analyzing and discussing the calculation results,the actual reaction sites were predicted finally.The conclusion of this study can provide certain theorical information for the synthesis of amphiphilic chitosan.