|
|
This laboratory introduced the process of recrystallizing crude acetanilide mixed with charcoal. Compounds can be purified by recrystalization because foreign molecules can seldom fir into the crystal lattice of another compound. The lab explored the method of isolating the impurity by breaking down the crystal structure by dissolution of the impure material in a suitable solvent and subsequent reformation of this crystal leaves the impurity in the solvent, and the solute remains relatively pure. 1 The technique of recrystallization involves the dissolution of the material to be crystallized in hot solvent followed by slow cooling of the solution. A moderate speed of crystal formation is desired. There are seven steps involved in successful recrystallization. They are: Selection of an appropriate solvent, dissolution of the material in the selected solvent, filtration of the hot solution to remove solid impurities, formation of crystals as the solvent cools, separation of crystals from the supernatant solution, washing the crystals, and finally drying the crystals.
|
