I am trying to synthesize a schiff base by reacting aldehyde with amine, using DMSO as solvent (as it is only soluble in this solvent). Before doing TLC, the sample was diluted with ethyl acetate and then applied to TLC plate. The mobile phase was ethyl acetate: methanol:hexane=3:1:1. I found it very hard to pull the compound from the baseline. In one try, it moved but produced a tailing. I did put 1 drop of ammonia in the mobile phase to avoid this. What should I do to produce a better resolution on TLC?
Your product is polar. So the reactants are. That's why increasing the ratio of methanol or replacing hexane with more polar DCM or chloroform would work.
Thanks for the suggestions. But on the web, I found an info that methanol should not be used at an amount of more than 10%. Is this right? And another query is that, what would be the appropriate purification technique for this schiff base? I tried silica based column chromatography but, due to its polarity, its very much hard to follow this technique. Should I go for recrystallization? If so, what would be the suitable solvent or solvent composition?
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