The kinetics of nucleophilic aromatic substitution by methoxide ion on 11 substituted arenes have been studied at 20-degrees-C using alkali metal (Li, Na, K) methoxides in methanol. Rate constants show a linear correlation with the excess basicity functions X for the three media, thus proving the applicability of the method to the interpretation of rate profiles in basic systems. The slopes m*double-ended dagger are shown to depend on the solvation of the transition state leading to the Meisenheimer complex intermediates. The relationship between m*double-ended dagger and standard state reactivities (log k(0)) is discussed. The inversion in the relative reactivities of 2- and 4-chloronitrobenzene with increasing base concentration is explained.

Kinetics of Nucleophilic Aromatic Substitution in Concentrated Solutions of Alkali Metal Methoxides in Methanol

BAGNO, ALESSANDRO;SCORRANO, GIANFRANCO;
1991

Abstract

The kinetics of nucleophilic aromatic substitution by methoxide ion on 11 substituted arenes have been studied at 20-degrees-C using alkali metal (Li, Na, K) methoxides in methanol. Rate constants show a linear correlation with the excess basicity functions X for the three media, thus proving the applicability of the method to the interpretation of rate profiles in basic systems. The slopes m*double-ended dagger are shown to depend on the solvation of the transition state leading to the Meisenheimer complex intermediates. The relationship between m*double-ended dagger and standard state reactivities (log k(0)) is discussed. The inversion in the relative reactivities of 2- and 4-chloronitrobenzene with increasing base concentration is explained.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11577/2463067
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact