季铵化N,O-羧甲基壳聚糖的制备及其合成条件优化

以N,O-羧甲基化度为85.6%的羧甲基壳聚糖(CM-CTS)为原料,w=0.40的NaOH水溶液为催化剂,3-氯-2-羟丙基三甲氯化铵(CTA)为接枝改性剂,在异丙醇介质中制备了具有良好水溶性的两性壳聚糖-季铵化N,O-羧甲基壳聚糖;分别以产物对模拟废水中的Cd+和Cr(Ⅵ)的絮凝去除率为基准对两性壳聚糖的合成条件进行了优化;用IR和1H NMR对产物的结构进行了表征。研究结果表明产物Cr(Ⅵ)的去除率更适宜作为合成条件的优化基准,且对应的优化条件为:季铵化反应时间为10.0 h,反应温度为60.0℃,mNaOH/mCM-CTS=0.50,mCTA/mCM-CTS=1.5;在此条件下合成产物对Cr(Ⅵ)的最大絮凝去除率为93.16%,对Cd2+的最大絮凝去除率98.52%。

Preparation of Quaternized N,O-Carboxymethyl Chitosan and Optimization of the Synthetic Conditions

A amphoteric chitosan with a higher solubility in water was prepared with 2-propanol as solvent,w=0.40 NaOH aqueous solution as catalyst,3-chloro-2-hydroxypropyl trimethlyammonium chloride(CTA) as grafting agent and N,O-carboxymethylchitosan(CM-CTS) with carboxymethyl degree of 85.6% as starting material.The synthetic conditions were optimized according to orthogonal experimens that based on the removal rate of Cd~(2+) and Cr(Ⅵ),respectively.The product was characterized by IR and ~1H NMR.The experimental resuls showed the removal rate of Cr(Ⅵ) could more suitably be regarded as the basis for the optimization of synthetic conditions.The optimized conditions were as follows the reaction time was 10.0 h,the temperature was 60.0(℃),m_(NaOH)/m_(CM-CTS)=0.50,m_(CTA)/m_(CM-CTS)=1.50.The maximum removal ratio of Cr(Ⅵ)and Cd~(2+) for the product prepared under these conditions could reach up to 93.16% and 98.52%,respectively.