Distillation of a Liquid Mixture


Distillation is a laboratory method for measuring the boiling point of a pure liquid and for purifying liquids. Distillation is used most often to separate a mixture of liquids into its component compounds, but the distilled materials are rarely pure. (This statement should make you reconsider any ideas you may have about the purity of “distilled” water). You will be performing distillations many times this year so this experiment is structured as an introduction to the basic ideas underlying distillation, and to provide experience with two of the most important variations on this procedure: simple distillation and fractional distillation.

Because distillation can feel like a complicated procedure, especially at first, we will keep the practical aspect simple. You and a partner will receive a two-component (binary) mixture of “whiskey flavorings”. You will distill your sample twice, once using simple distillation and again using fractional distillation, and you will make measurements that will allow you to assess which procedure, if either, provides reasonably pure samples of each flavoring. In the second week, you and your partner will make infrared (IR) measurements on your purified flavorings and try to identify each of them. If time permits (and if the computer lab is available), you will also use molecular models to predict the IR spectrum of each compound.