Preparation of Carboxymethyl Chitosan with High Substitution Degree by Phase Transfer Catalytical Method

[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.