Concerted aminolysis of diaryl carbonates: Kinetic sensitivity on the basicity of the nucleophile,nonleaving group,and nucleofuge |
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Authors: | Enrique A. Castro María Cubillos Rocío Iglesias José G. Santos |
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Affiliation: | Facultad de Química. Pontificia Universidad Católica de Chile. Casilla 306, Santiago 6094411, Chile |
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Abstract: | The kinetics of the reactions of 4‐methylphenyl, phenyl, and 4‐chlorophenyl 2,4,6‐trinitrophenyl carbonates ( 1 , 2 , and 3 , respectively) with a series of anilines and secondary alicyclic (SA) amines has been carried out spectrophotometrically in 44 wt% ethanol–water, at 25.0°C, ionic strength 0.2 M. The Brønsted plots (statistically corrected) for the reactions of carbonates 1 – 3 with anilines and SA amines were linear with slopes (βN) in the range of 0.69–0.78 and 0.45–0.48, respectively, attributed to a concerted mechanism. The negative values found for the sensitivity of log kN to the basicity of the nonleaving (βnlg) and leaving (βlg) groups are discussed. Anilines are more reactive than isobasic SA amines, probably because of the greater steric hindrance offered by the latter. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 604–611, 2012 |
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