Re: Hello. I'm looking for Carboxylic acids purification technics.

Usually, I remove the solvent under reduced pressure and then I do a
treatment with NaHCO3 5% and wash with ethyl acetate. After the NaHCO3
solution was carried to pH=2 I carry out several extractions with ethyl
acetate, dry with MgSO4 and remove the solvent.
At this point is were the troubles could start. Usually I have very
nice crude of reaction and I could cristalise in a good fashion or as
the last chance I could make a preparative TLC (I just need a couple of
miligrams). But when the crude is ugly I can't find an easy and
standarizable method to carry out the purification step.
The thing that I have in mind is to try with anion exchange
chromatography from the initial NaHCO3 solution. And elute with HCl or
NaCl. Other possibility is to filtrate the initial NaHCO3 with a
cationic exchange chromatography, just because i suspect that the
impuritys are aminoacids.
My major questions are about how to prepare the column. Do I've to
stabilise with the initial NaHCO3 solution? I known that the column
have to be thiner and larger than a common silica column, is that
correct? All this question are just because I don't have a Vogel-Like
textbook to extract this knowledge, and this is not a common task in my
lab.
Thanksssss.

PS: sorry by the length, and sorry by my english.

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