Kinetic and Mechanistic Investigation of the Reaction between Diethyl Acetylenedicarboxylate and Phthalimide Catalyzed by Triphenylarsine in Alcoholic Media

In this study, a comprehensive kinetic and mechanistic analysis was carried out for the reaction between diethyl acetylenedicarboxylate (DEAD) and phthalimide in methanolic media using UV–Vis spectroscopy. The effects of temperature, solvent environment, and the structure of dialkyl acetylenedicarboxylates on the reaction behavior were systematically examined. The kinetic data indicated an overall second-order process in which both DEAD derivatives and phthalimide contributed fractional orders close to unity. Further analysis revealed that the second stage of the transformation governs the overall rate of the reaction. Unlike reports employing triphenylphosphine (TPP), where distinct mechanistic pathways were proposed, triphenylarsine (TPA) in this system functions predominantly as an effective nucleophilic catalyst, accelerating the initial interaction and modifying the subsequent mechanistic profile. Thermodynamic parameters (ΔG‡, ΔS‡, ΔH‡, and Ea) were evaluated using temperature-dependent studies, providing deeper insight into the reaction pathway and the associated energy requirements.

کلیدواژه ها:

Kinetics ، Mechanism ، UV-Vis Spectroscopy ، phthalimide ، diethyl acetylenedicarboxylate