Preparation and properties of new lactose-based surfactants

A new group of nonionic saccharide-based surfactants, N-alkanoyl-N-methylla ctitolamines (alkanoyl: decanoyl, lauroyl, myristoyl, palmitoyl, stearoyl), were synthesized and characterized. Surface properties such as critical mi celle concentration, standard free energy of adsorption, standard free ener gy of micellization, surface tension reduction efficiency, effectiveness of surface tension reduction, surface excess concentration, and surface area demand per molecule as well as foaming properties (i.e., foam volume and fo am stability), contact angle, antimicrobial activity, and biodegradability were determined. The selected performance properties were evaluated in rela tion to commercially available alkyl polyglucosides (Glukopon 600 EC(HH)-a Henkel product), and oligooxyethylenated decyl (C10E4) and dodecyl (C12E5) alcohols. The foaming-stabilizing effect and contact angle suggest that the lactose-derived surfactants that were studied share some common properties with alkyl polyglucosides that are different from those with an oligooxyet hylene grouping. All tested N-alkanoyl-N-methyllactitolamines were practica lly nontoxic to bacteria and yeasts. These compounds are readily biodegrada ble in the Closed Bottle test inoculated with activated sludge. N-Alkanoyl- N-methyllactitolamines with lower chain lengths (C-10-C-14) biodegraded at a slightly faster rate. Biological properties showed that this class of com pounds fulfills all requirements needed for environmental acceptance.