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4‐Phenyl‐1,2,4‐triazoline‐3,5‐dione in the ene reactions with cyclohexene, 1‐hexene and 2,3‐dimethyl‐2‐butene. The heat of reaction and the influence of temperature and pressure on the reaction rate
Author(s) -
Kiselev Vladimir D.,
Kornilov Dmitry A.,
Kashaeva Helen A.,
Potapova Lyubov N.,
Konovalov Alexander I.
Publication year - 2014
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3277
Subject(s) - chemistry , enthalpy , ene reaction , cyclohexene , reaction rate constant , reaction rate , thermodynamics , volume (thermodynamics) , reversible reaction , standard enthalpy of reaction , equilibrium constant , medicinal chemistry , catalysis , organic chemistry , kinetics , physics , quantum mechanics
The values of the enthalpy (53.3; 51.3; 20.0 kJ mol −1 ), entropy (−106; −122; −144 J mol −1 K −1 ), and volume of activation (−29.1; −31.0; −cm 3 mol −1 ), the reaction volume (−25.0; −26.6; −cm 3 mol −1 ) and reaction enthalpy (−155.9; −158.2; −150.2 kJ mol −1 ) have been obtained for the first time for the ene reactions of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione 1 , with cyclohexene 4 , 1‐hexene 6 , and with 2,3‐dimethyl‐2‐butene 8 , respectively. The ratio of the values of the activation volume to the reaction volume (∆ V ≠ corr /Δ V r − n ) in the ene reactions under study, 1 + 4 → 5 and 1 + 6 → 7 , appeared to be the same, namely 1.16. The large negative values of the entropy and the volume of activation of studied reactions 1 + 4 → 5 and 1 + 6 → 7 better correspond to the cyclic structure of the activated complex at the stage determining the reaction rate. The equilibrium constants of these ene reactions can be estimated as exceeding 10 18 L mol −1 , and these reactions can be considered irreversible. Copyright © 2014 John Wiley & Sons, Ltd.