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Interaction of dimethyl carbonate with anilines in the presence of potassium methylate: Kinetics and the role of the base
Author(s) -
Mantrov Sergey N.,
Gordeev Dmitry A.,
Dashkin Ratmir R.,
Nefedov Pavel A.,
Seferyan Mary A.
Publication year - 2019
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.21308
Subject(s) - chemistry , dimethyl carbonate , aniline , substituent , aminolysis , deprotonation , potassium carbonate , reaction rate constant , inorganic chemistry , medicinal chemistry , catalysis , organic chemistry , kinetics , ion , physics , quantum mechanics
The kinetic patterns of the reaction between dimethyl carbonate and anilines in the presence of a potassium methylate as a catalyst were studied. The mechanism of aminolysis was clarified, which includes the detachment of the proton from the amino group of aniline and the subsequent attack of the resulting anion on the carbonyl group of dimethyl carbonate. It is shown that when the reaction occurs in the dimethyl carbonate‐methanol 3:1 system, the process can be described as an irreversible first‐order reaction in the aniline though the target reaction is complicated by side interaction between potassium methylate and dimethyl carbonate. The rate constants of the target reaction with substituted anilines and of the side reaction in the temperature range of 70‐90°C were determined. It is shown that the influence of the substituent on the reaction rate is described by the Hammett equation, with the constant of the reaction series being positive and the best correlation being achieved for σ‐scale. The results obtained are consistent with the proposed mechanism of the reaction and are explained by the facilitation of the aniline deprotonation with increasing acceptor properties of the substituent. Effective activation energies for the reaction of various anilines with dimethyl carbonate are found.