Some common ways to purify organic compounds include distillation, recrystallization, dialysis and extraction. Colorado University reveals distillation uses the evaporation of compounds to achieve purification, while Portland Community College states recrystallization works for organic solids at room temperature. Dialysis needs a membrane to filter various substances and acid-base extractions utilize aqueous solutions to purify organic liquids.
Distillation involves heating a liquid until it evaporates and then collecting and condensing hot vapors. Chemists note the boiling point of various substances that are collected in order to identify them. Less-volatile materials stay behind in the sample until they are boiled later in the distillation process.
Recrystallization purifies solids. The selection of a viable solvent is crucial to recrystallization. The process includes dissolving a solid near the boiling point of the solvent, and then the substance recrystallizes as the solvent cools. Impurities stay in the solution rather than become part of the solid.
Dialysis uses membranes to separate solids in a solution. Sample molecules that are larger than the membrane holes stay on one side of the barrier while buffer salts and small molecules migrate to the other side. Dialysis needs a large volume of buffer solution to work.
Acid-base extraction utilizes aqueous solutions of acids and bases to get certain substances to fall out of solutions as solids. These precipitates and solids are identified by melting-point analysis techniques.