Recrystalization is the process by which a solid compound is purified. Often times, solid compounds will contain impurities that are insoluable and therefore, removal requires the entire compound to be dissolved and then recrystalized. This is done by finding the best solvent for the compound, one that has low solubility at low temperatures, and high solubility at high temperatures. This means that when the solvent is near or is boiling, only then will the compound begin to disolve. One a compound is disolved with the proper solvent, cooling is allowed to happen at room temperature for crystals to form. If there is no crystal being formed, the container may be scratched so that the compound has a place to "cling" onto. Further crystal formation is induced by cooling the solvent in an ice bath. Once the largest amount of crystals are formed, the compound is then vacuumed to remove any solvent. To remove and residue of impurities, an ice cold solvent of minimal amount is poured onto the crystals. The yield of pure compound is naturally less than that of the original sample.
Recent comments