Comparative Study And Optimum Method Of Chitosan Monomer And Oligomers Preparation

This paper determined the optimum producing technology conditions of chitosan monomer and oligomers through lots of experiments and several preparation methods were compared for merit and shortcoming .D－glucosamine hydrochloride is one of the derivation of chitin monemer,it is an important kind of biochemicals and intermedium of medicine ,and it is well－liked in international market .We had verdict－crossing experiment with three factors and six levels . On the basis of ultimate yield ,monomer content ,optical rotation , chromaticity , crystal and so on ,we obtained optimum technology conditions . Meanwhile , we investigated the influence of orders of filtration craft and de-colorization craft on the product quality . Our experimental products are consistent with that of sigma Corp. by IR .This work establish an excellently technological guarantee for the future industrialization .Chitosan oligomers are the degraded product of chitin or chitosan , with means of chemical degradation or enzyme degradation or oxidizing degradation and so on . In recent years with further research , chitosan oligomers have showed distinctively and advantageously physiological activity and functionary character . We studied the preparation of chitosan oligomers using different degraded ways of oxidizing and microwave technology . Under the acid conditions , H2O2 as the oxidation ,we had the verdict－experiment with four factors and three levels , obtaining superior preparation technology of chitosan oligomers with molecule below 2000. Chitosan oligomers through microwave degradation have not been reported now . We demonstrated that this method is an excellent way which has many advantages such as energy-saving , pollution-relieving , time-saving and resource-saving by our experiments . Using different chitosans ,we studied the influence of pure solvent and salt effect on molecular weight under microwave. The final molecule weight ranged 1×105－10×105.By means of IR, we know that the positions of main peaks of chitosan are unchanged , and each peak strength changed while chitosan molecular weight reduced , which we testified that the way of oxidizing or microwave degradation is through dividing β－1.4－ glucoside band of chitosan.