This classical distillation exercise utilizes a novel scenario to introduce the concept of solvent recycling. The scenario introduces the student to a "real life" situation involving both purification and assessment of purity. The experimental procedure guides the student to the point at which they need to assess the purity. The students are asked to identify and select an appropriate technique for determining the purity of a volatile liquid. While the scenario letter does not tell the students to "do" green chemistry, the student will learn a green lesson in solvent recycling.
One way of expanding systematic green chemistry practices through the teaching lab is to collect and recycle waste acetone throughout the course of the semester. This can then serve as the source of the contaminated acetone for the subsequent semester. An added benefit to the lab is that it is a zero waste lab. Acetone that has been purified by this experiment can be used as wash acetone, or can be saved for the next time the experiment is performed. The collected pot residue, if containing only food coloring and acetone, can also be saved for the next time the experiment is performed.
Summary prepared March 2007 by Carl S. Lecher, Department of Chemistry at Marian College.
Lecher, C. S. Simple Distillation: Purification and Reuse of Acetone, Chemistry, Marian College, 2007