Question

Assume that a TLC analysis has shown that your target compound can be separated from a compound mixture by a CC separation in toluene. Unfortunately, the compound mixture does not dissolve in toluene (i.e. you cannot apply the compound as a solution in toluene). After solubility tests you find that the compound mixture dissolves in ethyl acetate. Can you apply the compound mixture as a solution in ethyl acetate, followed by the elution in toluene? Please explain.

Answer 1

The answer is No,

it would not be useful. Because Column chromatography depends on both Solubility and polarity.

Ethyl acetate is more polar than Toluene and also compound solubility is more in ethyl acetate.

once you apply compound mixture in ethyl acetate it will elute along with toluene because of solubility of the compound in ethyl acetate.

Hence you have to use the different percentage of non polar solvent (Alkanes preferably hexanes) mixture with ethyl acetate to purify through the column.