[NormalPolymer]

Hi all:

Just curious, can I separate a surfactant from a hydrophobic compound? My crazy idea is to dissolve the mixture in water and extract with organic solvent in which the hydrophobic compound can dissolve. The hydrophobic compound goes to the organic solvent phase and the surfactant goes to water phase. Does it make sense?

Thanks.

[fledarmus]

Depends on the surfactant - frequently you end up with three layers, a water layer, a hydrophobic layer, and an emulsion in the middle occupying more or less volume (up to the entire amount in the sep funnel!) depending on the concentration and nature of the surfactant. When I worked in the oil industry testing surfactants for use in tertiary oil recovery, that was one of the tests we used - how much volume did the emulsion occupy and how long was it stable? Many of those emulsions were stable for weeks!

If you are careful not to foam or shake your mixture you might have more success - put your bottom layer in a flask, add your top layer carefully, and stir without agitation. It takes a while to equilibrate since you don't have nearly as much surface area to transport your compounds from one layer to the other, but it might keep you from forming unbreakable emulsions. Especially since most of the methods for breaking emulsions (adding salt for example) drive the surfactant to the hydrophobic layer, which is what you are trying to avoid.

[Polytriazole]

Are you using an ionic or non-ionic surfactant?  If the surfactant is ionic, you might be able to alter the pH or salt content of your aqueous phase to make the surfactant more soluble in the aqueous phase.  If the surfactant is non-ionic, is it a polymer?  Because you might be able to precipitate the polymer surfactant and remove it that way.