Effect of acids and ZSM-5 as catalyst for chitosan depolymerization process

Abstract

Chitosan (CS) is a linear polysaccharide derived from chitin which is the second most abundant polysaccharide in the world. With its biocompatibility and non-toxic property, it has been used in various fields such as agriculture field, industrial field, biomedical field, or even chemical field. However, chitosan itself is a large molecule that is insoluble in water and this fact limits lots of their applications. To utilize this chitosan for the best results, there becomes to be more and more research on the conversion of chitosan into chitosan oligomers with expected molecular weights less than 3,900 Da or about 24 mer which have high anti-biomicrobial property that is suitable for advanced biomedical application. In this report, it carried out about chitosan depolymerization using two different kinds of acid including HCl and CH₃COOH along with ZSM-5 as a catalyst to achieve chitosan oligomers. The result showed that HCl showed greater results than CH₃COOH as about 30% of their depolymerized products are chitosan oligomer with molecular weight of 3800 Da which are in the range that preferred. While the appearance of ZSM-5 provided wider molecular weight distribution in both HCl and CH₃COOH condition.