SURFACE-ACTIVITIES, BIODEGRADABILITY AND ANTIMICROBIAL PROPERTIES OF NORMAL-ALKYL GLUCOSIDES, MANNOSIDES AND GALACTOSIDES

n-Alkyl alpha-and beta-glucopyranosides, alpha-D-mannopyranosides and beta-D-galactopyranosides with alkyl chains having from 8 to 12 carbon atoms were synthesized and their surface properties--such as static surface tension (gamma), critical micelle concentration (CMC), occupation area of molecule, dynamic surface tension and foaming properties, biodegradability and antimicrobial activities - were evaluated. Alkyl glcosides containing C8 to C12 carbon chains showed surface activities and critical micelle concentrations. D-Glucoside, D-mannoside and D-galactoside having the same alkyl chain showed similar surface tension lowering at CMC (gamma-(cmc)) and occupation area of the molecule at the surface. Among the alkyl glucosides, alpha-anomers were less hydrophilic than beta-anomers. All alkyl glycosides tested in this study were readily biodegraded by activated sludge of a municipal sewage plant compared to those of ethoxylated nonionic alcohols. The difference of the hydrophilic glycopyranoside group in biodegradability was not seen clearly. n-Alkyl glycosides containing C8 to C12 alkyl chains showed a broad spectrum of increasing antimicrobial activity. n-Dodecyl alpha-D-mannopyranoside was the most effective, the order of antimicrobial activity being mannopyranoside > glucopyranoside > galactopyranoside group. Members of this class of compounds exhibit the physicochemical and biological properties needed both for a wide range of applications and for environmental acceptance.