N,O-羧甲基化羟丙基壳聚糖的制备及结构表征

摘要

用NaOH作为催化剂,在异丙醇悬浮体系中环氧丙烷(PO)与壳聚糖(CS)在60℃下反应8h,制备取代度超过0.8的羟丙基壳聚糖(HPCS).HPCS在水溶液中与氯乙酸反应,制备了一种结构新颖的两性聚合物N,O-羧甲基化羟丙基壳聚糖(HPCMS),羧甲基取代度可控制在0.42～1.38之间.采用NMR和FTIR对产物结构进行表征.结果表明,在壳聚糖的羟丙基化改性过程中,C6位羟基首先与环氧丙烷反应,生成HPCS;在与氯乙酸反应过程中,HPCS上的羟基和氨基同时与氯乙酸发生取代反应.%A novel N,O-carboxymethyl hydroxypropyl chitosan(HPCMS) derivative was prepared through two steps reaction. Water-soluble hydroxypropyl chitosan ( HPCS) derivatives with degree of substitution of hydroxypropyl (DSHP) more than 0. 8 were synthesized by reacting chitosan with propylene oxide (PO) using alkali as catalyst; then HPCMS with the DS of carboxymethyl( DSCM ) ranging from 0. 42 to 1. 38 were prepared by reacting HPCS with chloroacetic acid under alkaline conditions. The structures of the polymers were characterized by FTIR and NMR. The results show that the alkylation mainly occur on the -OH groups at C6 in the reaction of chitosan with propylene oxide; and the -OH groups and -NH2 groups of HPCS are both alkylated in the reaction of HPCS with sodium chloroacetate.