An Organization Device for Visualizing Mechanisms and Regiochemistry Rationales in Electrophilic Aromatic Substitution

Abstract

Design and testing of a hand-held device, consisting of two sheets of card stock, presenting electrophilic aromatic substitution (EAS) data in an organized fashion, and designed to facilitate learning electrophilic aromatic substitution reactions is reported. The device includes a large amount of information with similar data grouped, and the groups are juxtaposed in order to facilitate pattern recognition and differentiation. This, in turn, facilitates visualization, retention, understanding, and use of the data presented. One sheet is placed over the other in order to visualize the mechanism between the substituted aromatic compound selected and the chosen reagent. It shows two aspects of EAS on separate pages and, then, demonstrates interactively how they interrelate. The two aspects are (1) the substitution itself, including the identity of the electrophile, the reagent(s) needed to generate it, and the substituent in the product and (2) the electronic effects of the groups in the aromatic compounds upon the intermediate(s) and the structure of the product. The effect of the use of the Electrophilic Aromatic Substitution Tool (also known as EAS-at-a-Glance) on the test performance of students enrolled in undergraduate organic chemistry was determined by a post-test-only control-group study. The subject samples were assigned to a control group and three device groups, differing with respect to use of the device. Results show that the EAS Tool enabled a better student performance (by 12.3% to 17.3%, depending upon the method of use), and that the best method of use is as an out-of-class supplement.