Crystallization:
The difference in the solubilities of an organic compound and that of the impurities present in it, in a suitable solvent, is the basis for this method of separation. A concentrated solution is prepared by dissolving the compound in a suitable solvent; the pure compound crystallizes out on cooling. The dissolved impurities are removed through filtration. The filtrate contains some amount of pure compound too. A compound containing impurities of comparable solubilities are purified by repeated crystallization.