Transmission of polar effects. Part 16. Ionisation of 8-substituted 1-naphthoic acids and the alkaline hydrolysis of their methyl esters

Abstract

Kirkwood–Westheimer calculations were carried out for the ionisation of three 8-substituted 1-naphthoic acids in 80%(w/w) 2-methoxyethanol–water at 25 °C. The reversed substituent polar effects are accounted for qualitatively and quantitatively for the 8-chloro and 8-bromo acids. For the 8-nitro acid the critical nature of the assumptions regarding the geometry is discussed. The rate coefficients for the alkaline hydrolysis of six methyl 8-substituted 1-naphthoates have been determined in 70%(v/v) dimethyl sulphoxide–water at 83.3 °C. All 8-substituents show very large steric ‘bulk’ retardations and their significance is discussed.