University Chemistry ›› 2026, Vol. 41 ›› Issue (4): 457-463.doi: 10.12461/PKU.DXHX202505036

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Estimating Delocalization Energies of 1,3-Butadiene and Benzene with Isodesmic Reactions: A Relatively Precise Approach

Mengfan Gong, Dongju Zhang   

  1. School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, Shandong Province, China
  • Received:2025-05-14 Accepted:2025-06-30 Published:2026-04-24
  • Contact: Dongju Zhang E-mail:zhangdj@sdu.edu.cn

Abstract: Delocalization energy serves as a fundamental concept for understanding the stability of conjugated organic molecules, with direct relevance to multiple core topics in structural chemistry education. Using 1,3-butadiene and benzene as representative examples, this study presents a refined approach for accurately estimating delocalization energies. The methodology incorporates the concept of isodesmic reactions while integrating experimental data from hydrogenation heats, reaction enthalpy changes, and quantum chemical computation results. Our calculations yield delocalization energies of 14.2 kJ·mol-1 for 1,3-butadiene and 127.6 kJ·mol-1 for benzene. The proposed method and obtained results not only facilitate students' conceptual understanding of delocalization in conjugated systems but also provide enhanced insight into the structure-property relationships of these fundamental organic compounds.

Key words: Delocalization energy, Isodesmic reaction, 1,3-Butadiene, Benzene, Computational chemistry