Kinetics of hydrolysis of sulphamic acid in concentrated perchloric acid solutions

Abstract

The kinetics of hydrolysis of sulphamic acid have been stuided in perchloric acid solutions (0.2–10.2 mol dm ^–3) at 48.5–80 °C. The measured first-order rate constant increases up to [H⁺]=ca. 2.0 mol dm ^–3 and then gradually decreases with increasing acidity. The rate law for the acid-catalysed hydrolysis of sulphamic acid (as distinct from that of the sulphamate ion) is Rate =k₂[H⁺][NH₃SO₃^–]a_w(where a_w is the activity of water) and A-2 mechanism is suggested.