Sulfonation Of Chitosan And Its Application

In this paper, the degree of deacetylation of chitosan was improved, then chitosan was sulfonated directly, sulfonated after hydroxylpropyl modification and xanthated. Finally, the solubility, antithrombogenicity and antibacterial activity of chitosan derivatives were studied.The main contents of experiment were as follows:The isopropanol was added to the system of deacetylation reaction, which made the reaction system become alkali-alcohol-water system from alkali-water system. The experiment results were: the deacetylation reaction of chitosan was easier to taken place in the alkali-alcohol-water system. The deacetylation degree and viscosity of product were all improved remarkably, the bigger the ratio of alcohol to water, the higher the deacetylation degree of product. At the same tune, the mechanism of the function of alcohol in deacetylation reaction was discussed.In the condition that the dose of formamide and chitosan was changeless, the influence of the temperature ,time and dose of chlorosulfonic acid on sulfonation reaction was studied. The mechanism of sulfonation reaction was discussed. The experiment results were: the best condition of the sulfonation reaction of chitosan is: the dose of chlorosulfonic acid is 4ml, the temperature is 70癈,the time is 4h. The sulfonation reaction was electrophilic reaction, SO? was electrophilic reagent.The water solubility and activity of chitosan were highly improved after chitosan was modified with isopropanol. The best condition of sulfonation reaction of hydroxylpropyl chitosan is: hydroxylpropyl chitosan 2g,chlorosulfonic acid 5ml, formamide 20ml, the reaction temperature is 70癈, the reaction time is about 3h. The sulfur content of sulfonated hydroxylpropyl chitosan is higher than sulfonated chitosan.On the basis of sulfonation reaction, in order to improve the sulfur content of chitosan derivatives as possible, chitosan was xanthated. The best reaction condition is: chitosan Ig, NaOH solution 5ml, the concentration of NaOH solution is 30%,CS212ml, the time is 6h, the temperature is 80 .The antibacterial activity and antithrombogenicity of chitosan and its derivatives were studied, the experiment result was: they all have antibacterial activity. Chitosan, sulfonated chitosan, sulfonated hydroxylpropyl chitosan have good antithrombogenicity, but xanthl chitosan has little antithrombogenicity.The relation between sulfur content, structure character and antithrombogenicity of chitosan derivatives was discussed. The experiment result was: on some certain extent, the higher the sulfur content, the better the antithrombogenicity, the relation between structure character and antithrombogenicity was complicated and should be studied furtherly in the future.The IR spectra ananlysis indicated that the structure of sulfonated chitosan and sulfonated hydroxylpropyl chitosan was similar to heparin. Because sulfonated hydroxylpropyl chitosan had better water solubility and antithrombogenicity, it may be further developed into novel heparin-like medicine and antithrombogenicity medicine.