[Objective] The study aimed to discuss the method for preparing the water-soluble carboxymethyl chitosan (CMC) and confirm the reactive conditions of preparing the CMC. [ Method] With the alcohol water solution as the reactive media, the phase transfer catalytical method was used to prepare the water-soluble CMC. The effects of the kinds of catalyst, the amount of catalyst, reaction temperature, reaction time and water-alcohol ratio on the substitution degree of CMC were investigated and the effecting law of the technology conditions on the substitution degree of CMC were discussed. [ Result] In the alcohol water reaction media, the phase transfer catalytical method was used to make for the chemical modification on the chitosan with the chloroacetic acid under the alkaline conditions and then the water-soluble CMC with high-substitute degree was synthetized. The method reduced the using amount of the organic solvent isopropyl alcohol and improved the substitution degree of the CMC. The better reactive conditions of preparing the CMC was follows: 6% hexadecyltrimethylammonium chloride as the catalyst, the reaction temperature of 60 ℃, reaction time of 4.0 h and water-alcohol ratio of 1:4. Under these conditions, the substitution degree of CMC reached 1.53. [Conclusion] The study provided the reference for preparing the CMC with different substitution degree.%[目的]探讨制备水溶性羧甲基壳聚糖( CMC)的方法,确定制备CMC的反应条件.[方法]以醇水溶液为反应介质,采用相转移催化法制备了水溶性CMC,考察了催化剂种类、催化剂用量、反应温度、反应时间和溶剂中水醇比对CMC取代度的影响,探讨了工艺条件对CMC取代度的影响规律.[结果]在醇水反应介质中,采用相转移催化法在碱性条件下用氯乙酸对壳聚糖进行化学改性,合成了水溶性的高取代度的CMC.该方法降低了有机溶剂异丙醇的使用量,提高了CMC的取代度.制备CMC的较好反应条件为:以6％的十六烷基三甲基氯化铵作催化剂,反应温度60℃,反应时间4.0h,溶剂中水醇比1:4(V/V).在此条件下,CMC的取代度为1.53.[结论]该研究为制备不同取代度的CMC提供参考.
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