Dual Studies on a Hydrogen-Deuterium Exchange of Resorcinol and the Subsequent Kinetic Isotope Effect

An efficient laboratory experiment has been developed for undergraduate students to conduct hydrogen-deuterium (H-D) exchange of resorcinol by electrophilic aromatic substitution using D₂O and a catalytic amount of H₂SO₄. The resulting labeled product is characterized by ¹H NMR. Students also visualize a significant kinetic isotope effect (k_H/k_D ≈ 3 to 4) by adding iodine tincture to solutions of unlabeled resorcinol and the H-D exchange product. This method is highly adaptable to fit a target audience and has been successfully implemented in a pedagogical capacity with second-year introductory organic chemistry students as part of their laboratory curriculum. It was also adapted for students at the advanced high school level.