Chlorine is substituted quantitatively from chloro-2, 4-dinitrobenzene by a variety of amines, including 'α-nucleophiles' such as methoxylamine or hydrazine, in 3: 2 dioxan–water. Second-order kinetics, first-order with respect to both reagents, are obtained in all cases. Primary n-alkylamines, spanning an interval of nearly five pKa′ units, nicely fit the extended Brønsted equation log k= 0· 63pKa′–8· 45, where k is the second-order rate coefficient ...
