Computational Study of Reaction Pathways between 2,6-Dimethylphenyl Isocyanide and Dimethyl Acetylene dicarboxylate in the Presence of 1,3-Dimethylbarbituric Acid: Activation Energy Analysis Using Density Functional Theory (DFT)

Zahra Soflaei Meimand¹

IOI Code : AAGF-ABFFFC
Publication : 9th International Conference on Applied Researches in Science & Engineering (carseconf.com/9th)
Abstract :
    In this study, the reaction pathways between 2,6-dimethylphenyl isocyanide and dimethyl acetylene dicarboxylate in the presence of 1,3-dimethylbarbituric acid were investigated using density functional theory (DFT). Three hypothetical reaction pathways were analyzed, and the results showed that Pathway 1, with the lowest activation energy (Ea = 15.2 kcal/mol) and the most stable transition free energy (ΔG‡ = 14.5 kcal/mol), represents the predominant reaction route, whereas Pathways 2 and 3, with higher Ea values (18.6 and 21 kcal/mol) and larger ΔG‡, are less favorable. Molecular interaction analysis indicated that hydrogen bonding in Pathway 1 stabilizes the transition state and reduces the activation barrier, while weaker interactions such as π-π stacking and van der Waals forces in the other pathways only slightly lower the Ea. Combined analysis of activation energies, ΔG‡, and molecular interactions revealed that the soft acidic catalyst guides the preferred reaction pathway, enhancing both the reaction rate and overall efficiency. This study highlights that DFT-based computational approaches provide a powerful tool for identifying preferred reaction pathways, designing targeted reactions, and optimizing the role of catalysts.

Keywords : reaction pathway sctivation energy molecular interactions soft acidic catalyst density functional theory (dft)