Modified Chitosan And Its Promotion Of Organic Reaction

There are very rich chitosan resources in China,which is the only alkaline polysaccharides in nature,and the content of chitosan is only less than that of cellulose.Because of its good biocompatibility and biodegradability,chitosan is a kind of good biological resource with broadly potiential prospects for development.Therefore,Focus on the research and development of chitosan,is of great significance in research.In this paper we applied chitosan derivatives,such as sulfonated chitosan and sulfonated chitin as a catalyst in some organic reaction to study the catalytic effect of the organic reactions,and we also prepared two kinds of novel chitosan derivatives which their adsorption effect on heavy metals of Cd(II)was studied.The main results are as follows:(1)A environment-friendly and efficient method for synthesis of 3,4-Dihydropyrimidin-2(1H)-ones catalyzed by sulfonated chitin(sulfonated chitosan)as an efficient catalyst under mild conditions is described.This method provides several advantages,such as environmental friendliness,simple work-up procedure,mild reaction conditions and high yields.(2)A novel chitosan derivative was synthesized by crosslinking reaction of chitosan Schiff base and sodium alginate,and then used as adsorbent for adsorption of Cd(II)ion.The structure of chitosan derivative was characterized and the adsorption behavior of Cd(II)ion was investigated.The equilibrium and kinetic data fitted the Langmuir and pseudo-second-order model well.Thermodynamic parameters exhibited that the adsorption process spontaneously and higher temperature made the adsorption easier.The results suggested that chitosan Schiff base could be considered to be promising materials for Cd(II)removal.(3)A novel chitosan Schiff base was synthesized by chemical reaction from O-carboxymethyl chitosan and o-Vanillin and used as adsorbent for adsorption of Cd(II).The structure of chitosan Schiff base was characterized.The adsorption behavior of Cd(II)was investigated.The adsorption isothermal data fitted well with the Langmuir isotherm equation,kinetic of adsorption was best described by a pseudo-second-order model.The results suggested that chitosan Schiff base could be considered to be promising materials for Cd(II)removal.