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Temprature dependence of the deuterium isotope effect in the deprotonation of some nitroalkanes by anionic bases
Author(s) -
Amin Mohammed,
Saunders William H.
Publication year - 1993
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.610060703
Subject(s) - nitroethane , chemistry , deprotonation , methoxide , kinetic isotope effect , hydroxide , methanol , deuterium , base (topology) , medicinal chemistry , solvent , protonation , solvent effects , organic chemistry , nitromethane , ion , physics , mathematical analysis , mathematics , quantum mechanics
The temperature dependences of rates and deuterium isotope effects were determined for the deprotonation of 1‐phenyl‐1‐nitroethane (1), its analogue 1‐ d , 1‐phenyl‐2‐nitropropane (2) and its analogue 2‐ d by methoxide in methanol, ethoxide in ethanol, hydroxide/methoxide in 50% (v/v) methanol–water and hydroxide in water. The isotope effects varied little with substrate or solvent–base combination. k H / k D at 30°C was between 6·0 and 7·1 in all cases. The temperature dependences varied considerably [ A aH / A aD = 0·14–1·35 and E aD – E aH 0·95–2·29 kcal mol −1 (1 kcal = 4·184 kJ)]. A aH / A aD was lower with 1‐phenyl‐1‐nitroethane than with 1‐phenyl‐2‐nitropropane, but there was no consistent variation with solvent/base.