Kinetics and equilibrium data for base-catalysed addition of ethanol to β-nitrostyrene

Abstract

The kinetics of the addition of ethanol to β-nitrostyrene catalysed by sodium ethoxide has been studied. The observed rate equation is R=A[β-nitrostyrene]+B, where A and B are constants which depend on the initial concentrations of the olefin and catalyst. The mechanism of the reaction consists of reversible addition of the ethoxide ion to the olefin, followed by rapid protonation of the intermediate carbanion. A general approach has been developed for determining the forward (k₁) and backward (k_–1) rate constants of the addition step, which are (1·7 ± 0·3)× 10² l mol^–1 min^–1 and (1·1 ± 0·4)× 10^–6 min^–1, respectively.