Metal−Acetylacetonate Synthesis Experiments: Which Is Greener?

A procedure for teaching green chemistry through laboratory experiments is presented in which students are challenged to use the 12 principles of green chemistry to review and modify synthesis protocols to improve greenness. A global metric, green star, is used in parallel with green chemistry mass metrics to evaluate the improvement in greenness. The methodology is exemplified with the search for the greenest metal−acetylacetonate synthesis experiment commonly included in the teaching laboratory literature. Green star responds holistically to a large number of features that have to be considered when the greenness of a process is under discussion because it involves an assessment of all the relevant twelve principles of green chemistry in a systemic way. The advocated procedure allows students to become familiar with both the 12 principles and green chemistry mass metrics and to gain experience in changing synthetic chemistry to improve its greenness.