Studies On Synthesis And Properties Of Chitosamine Surfactants

Glucosamine surfactants as the important natural derived surfactants possess goodsurface activities, foamability, emulsibility and moisture-absorption andmoisture-retention properties, at the same time, they also retained the uniquecharacteristics of chitin, such as non-toxicity, harmlessness, good biocompatibility andgood biodegradability. In this paper, the synthesis and properties of aliphaticcarboxylate glucosamine surfactants and an amphoteric glucosamine surfactant werestudied.Glucosmine hydrochloride （GAH） was prepared by the hydrolysis of chitin in theconcentrated hydrochloric acid solution. Series of aliphatic carboxylate glucosaminesurfactants, such as glucosamine caprylate （GAC）, glucosamine decanoate （GAD） andglucosamine laurate （GAL） were synthesized by reactions of fatty acid withglucosamine （GA） which was prepared by glucosamine hydrochloride （GAH） andtriethylamine. The appropriate synthesis conditions of GAL are as follows: mole ratioof GA to lauric acid is1.0∶1.1,6mL water as reaction medium, tempreture30℃,and time8h. Under the above conditions, the yield of GAL is69.2%. The structuresof the aim products were characterized by IR analysis and nitrogen content analysis.All the three aliphatic carboxylate glucosamine surfactants are soluble in water andpossess good surface activities; their critical micelle concentration （cmc） values are1.09×10^-3,8.51×10^-3and3.16×10-4mol·L^-1at25℃, respectively, the minimumsurface tension （γcmc） values are35.3,30.1,28.83,28.2mN·m^-1, respectively. Thehydrophile-lipophile balances （HLB） are11.82,10.87and9.92, respectively. All ofthem have certain foamability, good emulsifying ability to liquid paraffin and goodcompatibility with dodecyl dimethyl betaine (BS^-12), Tween80, hexadecyl trimethylammonium chloride （1631） under experimental conditions. As the length ofhydrophobic carbon chain increasing, surface activity, emulsifying abilitiy and foamability enhanced.6-O-carboxymethyl glucosamine （CMG） was synthesized with chloroacetic acidand glucosamine （GA） which was prepared by glucosamine hydrochloride （GAH） withKOH. Then an amphoteric glucosamine surfactant (2-hydroxy^-3-dodecyl dimethylquaternary ammonium) propyl-6-O-carboxymethyl glucosamine （QCMG） wasprepared by epoxypropyl dodecyl dimethyl ammonium chloride （DTGA） reacting with CMG. The appropriate synthesis conditions of QCMG are as follows: mole ratio ofCMG to DTGA is1.0∶1.1, mixture of20mL isopropy and5mL water as reactionmedium, temperature55℃, and time6.0h. Under the above conditions, the yield ofproduct is73.2%. The structures of the QCMG were characterized by IR analysis andnitrogen content analysis. QCMG is soluble in water, slightly soluble in methanol,ethanol, insoluble in other common organic solvents. QCMG possesses surface activity.The γcmc, cmc, saturated adsorption amount （Γmax）, saturated adsorption area （Amin） andfree energy of micellisation（ΔGcmc） of QCMG at25℃were calculated as25.87mN·m^-1,0.001mol·L^-1,3.78×10^-10mol·cm^-2,0.44nm²and^-17.13kJ·mol^-1,respectively. QCMG possesses certain foamability, moisture-absorption andmoisture-retention properties, good emulsifying ability to liquid paraffin and goodcompatibility with dodecyl dimethyl betaine (BS^-12), Tween80, hexadecyl trimethylammonium chloride（1631） under experimental conditions.