Sciencemadness Discussion Board

Purifying condensation-reaction products.

FrankMartin - 30-10-2010 at 18:46

As an example I want to remove the glycerine from the reaction product:

Glyceryl Cocoate + 3 (Monoethanolamine) = 3 (Coconut Monoethanolamide) + glycerine.

The reaction product in one isotropic mix, and the reaction lies to the right.

Is there an agent that when added to the product mix will dissolve in the glycerine component causing it and the glycerine to separate as one phase? I have already tried salt, borax, and soda ash. Sulfuric acid works but discolours everything. Water solutions of possible salts form annoying emulstions.

Please help.

not_important - 30-10-2010 at 19:08

The fatty acid monoethanol amid is a decent detergent and somewhat of a solvent. I can't think of a common solvent system that I'm confident would do a decent job of separation, especially as the desired product has a hydroxyl group too. Perhaps aromatic or aliphatic hydrocarbon solvents, the triol glycerol will have low solubility while the long CH2 chain __may__ give enough solubility to the amide.

Possible better way to do what you want to do is transesterfy to the methyl esters which are not too difficult to separate from the glycerol then convert that to the amide by adding the ethanolamine and an acid catalyst then distilling off methanol. You'll be faced with the possibility of the hydroxyl of the ethanolamine esterfying with the fatty acid I've no idea on the relative reaction rates for the hydroxyl vs amine

.