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Recrystallization

Quick Reference
Also Known AsFractional crystallization, purification by crystallization, recrystallisation

What is Recrystallization?

Recrystallization is a purification technique used to remove impurities from solid compounds by dissolving them in a hot solvent (in which the compound has greater solubility at high temperature) and then slowly cooling the solution to form purified crystals while impurities remain in solution. It is one of the most important laboratory and industrial purification methods for solid organic compounds.

Properties & Characteristics

Based on differential temperature-dependent solubility. Steps: dissolve in minimum hot solvent, filter hot (remove insoluble impurities), cool slowly (form pure crystals), filter cold (collect crystals), dry. Good solvent: large solubility difference between hot and cold. Common solvents: ethanol, water, ethyl acetate, acetone.

Uses & Applications

Purifying organic compounds after synthesis. Pharmaceutical manufacturing (API purification). Food industry (sugar refining by recrystallization). Growing crystals for X-ray diffraction analysis. Industrial chemical purification. Teaching laboratory technique.

Safety Information

Solvents used may be flammable (ethanol, acetone, ethyl acetate) or toxic. Use fume hood. Hot solvent handling — burns risk. Vacuum filtration — implosion risk with cracked glassware. Filter hot solution quickly to prevent premature crystallization.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Recrystallization
Synonyms Fractional crystallization, purification by crystallization, recrystallisation

Frequently Asked Questions

Recrystallization is a purification technique used to remove impurities from solid compounds by dissolving them in a hot solvent (in which the compound has greater solubility at high temperature) and then slowly cooling the solution to form purified crystals while impurities remain in solution. It is one of the most important laboratory and industrial purification methods for solid organic compounds.

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