I am conducting a Schiff base reaction where one of the reactants and product exhibit similar solubilities. However, the product also show solubility in water, unlike the reactants. After evaporating the reaction mixture to dryness, the resulting solution forms an oily product when water is added.
Anytime you need to separate two compounds, you need to look for differences. If their solubilities are very similar, then look for other differences.
• is one basic and the other isn't? (dissolve in acidic water, then extract the nonbasic compound with an organic solvent)
• is one acidic and the other isn't? (dissolve in basic water, then extract the nonacidic compound with an organic solvent)
• is one volatile and the other isn't? (separate by fractional distillation)
• do they differ in binding strength to stationary phases? (separate by column chromatograph. Watch out, though, because some basic compounds like Schiff bases tend to stick on silica or acidic alumina. Either use basic alumina or pre-treat the column with a solution of a more-basic organic in your eluting solvent before you try to separate your compounds)
While conducting a Schiff base reaction don't use water as a solvent. Importantly don't use water as solvent for the product because it will lead to reactant itself by hydrolyzing the azomethine group. Use some other organic solvents in which your reactant and product get soluble.
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