【摘要】 以高脱乙酰化的壳聚糖为主要原料 ,在乙酸水溶液 -乙醇 -吡啶介质中 ,实现了壳聚糖的 N位均相乙酰化反应 ,制备了脱乙酰度为 5 0 %左右 ,在 p H=1～ 14范围内具有良好水溶性的壳聚糖。重点考察了乙酸酐用量对脱乙酰度的影响 ,结果表明 ,当乙酸酐用量与壳聚糖的摩尔比在 2 .0左右时 ,产物的脱乙酰度接近 5 0 % .通过对所用的高脱乙酰度壳聚糖特性粘度 [η]的测定 ,间接得到了产物的分子量为 1.66×10 5左右。对产物进行了 FT- IR及 1H- NMR表征 ,谱图中与乙酰胺基有关的信号均发生了变化 ,表明了乙酰化反应的发生。更多还原

【Abstract】 Water soluble chitosans with a deacetyla ti on degree around 50%, which exhibit good water solubility in wide pH range from 1 to 14, were prepared by acetylation of chitosan at N position with acetic anhy dride in a homogeneous medium known as acetic solution／alcohol／pyridine system . The result shows that the deacetylation degree of products approach 50% when molar ratios of acetic anhydride to chitosan are around 2.0. Molecular weigh t was obtained indirectly by measuring ［η］ of raw chitosasn material and the value is equal to 1.66×105. The products were characterized by FT-IR and 1H-NMR, and the occuring of acetylation reaction of chitosan was man ifested.更多还原