Substituent effects on the condensation of nitrosobenzene with para- and meta-substituted anilines in acetic acid–sodium acetate buffered aqueous ethanol solutions

Abstract

The reaction of nitrosobenzene with meta-and para-substituted anilines has been studied in 94% (v/v) ethanol buffered with acetic acid and sodium acetate solutions. A linear Yukawa-Tsuno correlation was obtained (p -2.1 4; correlation coefficient 0.990; r 0-741 ). AAGp Values for p-nitroaniline and ethyl p-aminobenzoate were obtained. It is suggested that two mechanisms can explain the data gathered. The kinetic behaviour of the reaction as a function of acetic acid and sodium acetate concentration in the buffer solution was also studied.IN spite of their importance in chemical and biochemical processes, reaction mechanisms involving the nitrosogroup have not received much attention.1-3Ueno and Akiyoshi4 studied the kinetics of the reaction of aniline with substituted nitrosobenzenes in glacial acetic acid. They suggested a reaction mechanism in which the attack of aniline on the nitrosobenzene 1

Kinetics of the oxidation of aromatic C-nitroso compounds by nitrogen dioxide

“…There are several studies of the kinetics of bimolecular reactions of substituted nitrosobenzenes 1-4,12,25-31 and all of these, studied over a range of temperatures, have large negative entropies of activation. Thus the oxidation reactions 1, 25 have ∆S ‡ values in the range Ϫ109 to Ϫ138 J mol Ϫ1 K Ϫ1 , the condensation reactions 12, 26 have ∆S ‡ values in the range Ϫ227 to Ϫ264 J mol Ϫ1 K Ϫ1 , the Diels-Alder reactions 29, 30 have ∆S ‡ values in the range Ϫ123 to Ϫ145 J mol Ϫ1 K Ϫ1 and the radical addition reactions 31 have ∆S ‡ values in the range Ϫ93 to Ϫ129 J mol Ϫ1 K Ϫ1 . Our values for ∆S ‡ are similar to those for the oxidation, Diels-Alder and radical addition reactions.…”

Addition, Reduction, and Oxidation Reactions of Nitrosobenzene

“…The condensation at pH smaller than about 9 follows second-order kinetics, first order each in nitrosobenzene and in aniline. [130][131][132][133][134][135][136][137] The reaction is general acid catalyzed131'135-137 and involves reaction with water and hydronium ions. Brpnsted plots of logarithms of catalytic constants as a function of pK& of the carboxylic acid components of the buffer used are linear and their slopes correspond to Brpnsted coefficient a varying from 0.39 to 0.34 for reactions of anilines with substituted nitrosobenzenes and from 0.34 to 0.28 for reactions of nitrosobenzenes with para-substituted anilines.…”