This melting point study experiment is an adaptation of the solventless aldol reaction experiment found in Green Organic Chemistry Strategies, Tools, and Laboratory Experiments by Doxsee and Hutchison. This adaptation focuses on the proper determination of melting points and the effect of impurities on melting points. Three melting points are determined: the melting point for each of the starting materials and the melting point of the unpurified product. The students are to focus on making an accurate measure of the starting materials melting points (compared to tabular data), synthesize the product and dry it, and then determine the melting range of the product.
The melting point of the reactants matched well with tabular data when performed by students. The product yield ranged from about 80% - 105% and the melting range for the product started at about 150o C and was sufficiently broad to indicate the presence of impurities. Students found this experiment interesting and left with a good understanding of how to measure (and use) melting points and ranges.
Summary prepared November, 2008 by John E. Thompson at Lane Community College.
Thompson, J. E. Melting Point Study of a Solventless Reaction, Science Division, Lane Community College, 2008