The reactivity of p-nitrophenyl esters with surfactants in apolar solvents. VII. Substituent effects on the reactivity of 4'-nitrophenyl 4-substituted benzoates in benzene solutions of dodecylammonium propionate and butane-1,4-diamine bis(dodecanoate)

Abstract

The rate of decomposition of a series of 4'-nitrophenyl 4-substituted benzoates has been measured at 341 K in benzene solutions of dodecylammonium propionate and butane-1,4-diamine bis-(dodecanoate). The bimolecular rate constant due to general acid-general base catalysis from the head-group components of the surfactants is dependent on the nature of the substituents, and the rate data have been correlated by Hammett σ and σ⁺, Tsuno-Yukawa, and Taft dual substituent parameter linear free energy relationships. The reactivity of the esters has also been compared with the ¹³C n.m.r. chemical shift of their carbonyl carbon atoms. The results are consistent with a mechanism involving a general-acid-catalysed aminolysis of the unprotonated ester.