Using Group-Inquiry to Study Differing Reaction Conditions in the E2 Elimination of Cyclohexyl Halides

In this experiment, students individually conduct one of several variations of an E2 dehydrohalogenation reaction on a cyclohexyl halide substrate for 30 min, which is sufficient only for a partial reaction to occur. The variations examine reaction conditions including different leaving groups, decreased reaction temperature, or reduced base concentration. Analysis of the quenched reaction products by GC or NMR allows students to compute the percent completion of their individual reaction. In a subsequent lab, the student results are compiled and averaged, and statistics are generated. The students perform a collaborative group analysis to draw conclusions as to how the different factors affected the rate of reaction based on percent completion and the impact of any errors observed. The statistical compilation of data from repeated trials for the group analysis demonstrates to students an approach to research that is analogous to real-world research technique. (Contains 1 scheme and 1 table.)