Kinetics and products of the degradation of chitosan by hydrogen peroxide
K L Chang1, M C Tai, F H Cheng
1Department of Food Science, National Taiwan Ocean University, 2 Peining Road, Keelung 20224, Taiwan, Republic of China. klchang@mail.ntou.edu.tw
Abstract:
Low concentrations of hydrogen peroxide induced random degradation of partially deacetylated chitin and chitosan. Average molecular weight decreased in accordance with first-order kinetics. The degradation rate was much faster than that of the ultrasonic degradation, and it was comparable to that of the enzymatic hydrolysis of chitosan. Chain-end scissions occurred after chitosan was degraded severely and produced significant amounts of oligosaccharides at temperatures > or =80 degrees C. Universal calibration moderated the change in molecular weight more closely than that calculated by the usual calibration using pullulan standards. Trace amounts of transition metal ions and the amino groups in chitosan were critical to the breakdown of the beta-1,4 glycosidic linkages. HPLC results of glucosamine and chito-oligosaccharides could be characterized by correlating the logarithmic values of retention time with the degrees of polymerization. The formation of glucosamine and chito-oligosaccharides depended on the concentration of H(2)O(2), temperature, and the physicochemical property of chitin/chitosan.
Related Concept Videos
Catalysis
Autoxidation of Ethers to Peroxides and Hydroperoxides
Regioselectivity of Electrophilic Additions-Peroxide Effect
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Oxidation of Alcohols
The process of oxidation in a chemical reaction is observed in any of the three forms:
Catalysis


