Evolving Mechanistic Understanding of Electrophilic Aromatic Substitution: An Inquiry-Based Computational Chemistry Activity on Anisole Chlorination

Abstract

This work presents an inquiry-based learning activity that introduces upper-division undergraduates to reaction mechanism analysis using computational chemistry. In a case study of anisole chlorination, students employ density functional theory (DFT) calculations to investigate the classical σ-complex mechanism and the trimolecular pathway involving HCl or Cl₂ in CCl₄ (energy profiles may differ in polar protic solvents). The activity reframes the standard electrophilic aromatic substitution (EAS) mechanism with added mechanistic insight. Implemented as a take-home project with in-class support, it develops skills in model evaluation, data interpretation, and evidence-based reasoning. Student feedback shows increased confidence with computational tools, deeper understanding of EAS, and appreciation of evolving mechanistic models. This activity supports integration of theoretical research into the curriculum to foster critical thinking.