Rates of formation of isoperthiocyanic acid (5-Amino-1,2,4-dithiazole-3-thione) from thiocyanate in aqueous solution

Abstract

The rates of formation of 5-amino-1,2,4-dithiazole-3-thione from potassium thiocyanate in aqueous sulphuric acid have been studied spectrophotometrically. They show close to third-order dependence on thiocyanate concentration and linear dependence on the Hammett acidity function, h-. Between 25 and 45� the rate constant is given by the Arrhenius expression k = 9.27 x 10-5exp(-8800/T) 1.2 mole-2 sec-1 A mechanism is proposed.