Recrystallify

Recrystallify is a process used to purify solid compounds. It involves dissolving an impure solid in a minimal amount of a hot solvent, then allowing the solution to cool. As the solution cools, the solubility of the desired compound decreases, causing it to form pure crystals. Impurities, which are either more soluble or less soluble in the solvent, tend to remain dissolved in the solution or are excluded from the crystal lattice.

The choice of solvent is crucial for successful recrystallization. An ideal solvent will dissolve the desired compound well when hot but poorly when cold. It should also dissolve impurities readily at all temperatures or not at all. Common solvents include water, ethanol, acetone, and hexane, depending on the polarity of the compound being purified.

The process typically begins with heating the impure solid in the chosen solvent until it completely dissolves. The hot solution is then filtered, if necessary, to remove insoluble impurities. Next, the solution is allowed to cool slowly. Slow cooling promotes the formation of larger, purer crystals. Once crystallization is complete, the pure crystals are separated from the remaining solution (mother liquor) by filtration. The crystals can then be dried to remove any residual solvent.

Recrystallization is a widely used technique in organic chemistry for the purification of synthesized compounds and for isolating pure substances from natural sources. It is a relatively simple and effective method for obtaining high-purity crystalline materials.