Recrystallization

Recrystallization is a process used in chemistry laboratories to purify organic compounds that are solids at room temperature. The identity of a compound can be found using recrystallization methods in conjunction with other procedures. In organic chemistry lab, an unknown compound was given to recrystallize and identify. In order to start with the recrystallization process, one had to first decide the preferred solvent to dissolve the unknown compound. Five different solvents were available ,water, methanol, pure ethanol, hexane and toluene, to test for the most effective solvent for the unknown. Once determined, the student boiled the solvent on a hot plate and slowly added drops to the premeasured erlenmeyer flask containing about 250 mg of the unknown. Soon after, the student placed the dissolved solution on the bench to cool and then into an ice bath to allow crystal formation. The following steps included using a suction filtration to remove as much liquid as possible and then scrape crystals onto a filter paper to weigh. In addition to recrystallizing the unknown, the student measured its melting point, which is another physical property used for compound identification. Performing recrystallization in combination with finding the melting point, will lead to the identification of an organic compound.