SYNTHESIS AND AGGREGATION PROPERTIES OF DIALKYL POLYOXYETHYLENE GLYCEROL ETHERS

Two series of symmetric 1,2-dialkyl-rac-glycerol ether surfactants con taining a polydisperse non-ionic monomethyl polyoxyethylene glycol (MP EG) head group have been prepared using one of two similar four stage reaction pathways. Both schemes start with isopropylidene-rac-glycerol . In the first scheme the unifunctional MPEG was brominated and added to isopropylidene-rac-glycerol directly. In the second pathway the und erivatized MPEG was attached to isopropylidene-lac-glycerol via a tosy l glycerol derivative. In both reaction schemes the alkyl chains were introduced onto the monomethyl polyoxyethylene glycerol using a Willia mson ether type reaction. A third, six stage, synthetic route allowed the production of asymmetric 1,2-dialkyl-rac-glycerol ether surfactant s. In this scheme the first alkyl chain was added to isopropylidene-ra c-glycerol directly; while the second chain was added after selective (trityl group) protection of the primary hydroxyl of the monoalkyl gly cerol ether. In this route the polyoxyethylene glycol (PEG) chain was added terminally. In all schemes the crude surfactants were purified e ither by column chromotography or by a simple but effective washing an d molecular distillation procedure. The aggregation behaviour of the n ovel surfactants in aqueous solution is reported, and general trends n oted as to the influences of the hydrophobe and head group lengths on the nature of the aggregates formed.