A pulse radiolysis study of the temperature dependence of reactions involving H, OH and e -aq in aqueous solutions

Abstract

Within the 20–80°C temperature range, the rate constants and activation energies were measured for hydrogen atoms reacting with hydrogen peroxide ( k = 5.0 × 10 7 mol -1 dm 3 s -1, E act = 16.4 kJ mol -1), molecular oxygen ( k = 1.35 × 10 10 mol -1 dm 3 s -1, E act = 10.6 kJ mol -1) and the ferricyanide ion ( k = 6.2 × 10 7 mol -1 dm 3) s -1, E act = 9.3 kJ mol -1). Other reactions studied within the same temperature range were: the solvated electron reacting with oxygen ( k = 1.9 × 10 10 mol -1 dm 3 s -1, E act = 11.0 kJ mol -1), and with nitrous oxide ( k = 9.6 × 10 9 mol -1 dm 3 s -1), E act = 18.9 kJ mol -1); the bimolecular reaction of hydroxyl radicals (2 k = 7.2 × 10 9 mol -1 dm 3 s -1, E act = 7.7 kJ mol -1); and the reduction of the ferrocyanide ion by .CH 2OH ( k = 3.8 × 10 9 mol -1 dm 3 s -1, E act = 4.8 kJ mol -1). The rate constants are the values at 25°C and are accurate to 10–12%.