The Nitroalkane Anomaly

The effect of substituents on the reaction of nitroalkanes with base is analyzed in terms of two interactions which influence both rate and equilibrium constants and two others which affect the rates alone. The results of these calculations serve to explain the Brønsted relation with negative exponent given by data for the series nitromethane, nitroethane, and 2-nitropropane reacting with hydroxide ion, and also the Brønsted exponents greater than unity recently observed for the reactions of aryl-substituted nitroalkanes with hydroxide ion and other bases.