Abstract Addressing student misconceptions regarding the differing reactivity patterns of alkyl halides and alcohols in elimination reactions,this study employs Frontier Molecular Orbital(FMO) theory to elucidate the underlying mechanistic principles.Comparative analysis of the orbital energy matching requirements reveals the quantum chemical basis for the difficulty of E2 elimination in alcohols lacking β-electron-withdrawing groups,the high energy of the σ*(C—O) LUMO orbital results in a large energy gap with the HOMO of common bases.In contrast,alkyl halides readily undergo reaction due to the significantly lower energy of the σ*(C—X) orbital.Furthermore,using fluoroalkanes as a model system,the fundamental distinction between E1cb and E2 mechanisms(carbanion stabilization versus a concerted transition state) is clarified.This approach promotes student understanding of the electronic effects governing the reaction outcomes,effectively resolving student confusion.
JI Cong-Bin, HU Xin, ZHENG Jie. Mechanistic Analysis of Reactivity Differences in Elimination Reactions of Alkyl Halides vs.Alcohols Under Strong Basic Conditions[J]. Chinese Journal of Chemical Education, 2026, 47(6): 127-129.
