The Chitooligosaccharides Class Preparation And Properties Of The Surfactant

In this paper, the controllable depolymerization of chitosan by hydrogen peroxide under neutral conditions is studied in detail, and chitooligosaccharide, a good water-soluble low-molecular-weight depolymerized product of chitosan, has been prepared by this method. The number-average molecular weight of chitooligosaccharide is determined by terminal group method. Gel chromato-graphy, thin-layer chromatography are used to isolate, identify the chitooligo-saccharide, and the structure of chitooligosaccharide is affirmed by IR spectroscopy, 1~H NMR, and (13)~C NMR. For the first time, three series of new functional derivatives of chitooligosaccharide------(2-hydroxyl-3-butoxy) propyl-chitooligosaccharide, (2-hydroxyl-3-octoxy) propyl-chitooligosaccharide, (2-hydr-oxyl-3-dodeoxy) propyl-chitooligosaccharide, (2-hydroxyl-3-cetoxy) propyl-chito-oligosaccharide, (2-hydroxyl-3-nonylphenoxy) propyl-chitooligosaccharide; butyryl-chitooligosaccharide, hexanoyl-chitooligosaccharide, octanoyl-chito-oligosaccharide, caprinoyl-chitooligosaccharide, dodecyl-chitooligosaccharide, myristoyl-chitooligosaccharide, palmitoyl-chitooligosaccharide, stearoyl-chito-oligosaccharide, oleoyl-chitooligosaccharide; (2-hydroxyl-3-dodecyldimethyl -quaternary ammonium) propyl-chitooligosaccharide, (2-hydroxyl-3-myristyl-dimethyl-quaternary ammonium) propyl-chitooligosaccharide, (2-hydroxyl-3-palmityldimethyl-quternary ammonium) propyl-chitooligosaccharide------have been synthesized by chitoolidosaccharide reacted with alkyl glycidyl ether, acyl chloride, epoxypropylalkyldimethyl ammonium chloride, respectively. The suitable synthesis conditions of those new products have been studied. The structures of them are affirmed by IR spectroscopy, 1~H NMR, (13)~C NMR and Elemental Analysis; the configurations of them are also analyzed by theoretical calculation of quantum chemistry. Influences of the length of hydrophobic group, the degree of substitution on the solubility, surface activity, emulsifying property, foam property, hygroscopicity and humidity-retaining ability, compatibleness of those new products have been studied in detail. The experimental results show that all the new chitooligosaccharide derivatives are soluble in water (insoluble in ordinary organic solvents); all possess good surface activity which is concerned with the length of hydrophobic group and degree of substitution of the new compounds. Alkoxyhydroxylpropylchitooligosaccharide and quaternary ammo-nium-hydroxylpropylchitooligosaccharide possess certain emulsifying property, good hygroscopicity and humidity-retaining ability; the former also possessesgood compatibleness, the latter also possesses good generating and stabilizing foam ability. Consequently, the new three series derivatives of chitooligo-saccharide are hopeful to be used in foodstuff, medicament and cosmetics etc. as functional additives. Furthermore, depolymerization of chitosan by Fenton reagent and the influence of molecular-weight on the fundamental physical chemistry properties, applied functions of nonionic chitosan surfactant---(2-hydroxyl -3-dodeoxy) propyl-hydroxylpropylchitosan are also studied in detail for the first time in this paper.