Recrystallization

Recrystallization involves dissolving crystals in a minimum amount of hot solvent to separate your compound of interest from impurities using filtration.

It is crucial that your compound of interest and impurities show different solubilities in the chosen solvent. For example, if the compound of interest is more soluble in the hot solvent, then the impurities will remain solid, and they can then be filtered out.

After filtration, the solution is allowed to cool. This will slowly precipitate out the compound of interest.

Figure 1: Image showing how recrystallization removes impurities from deformed crystals to produce pure, regular crystals.