Abstract: In order to solve spontaneous decomposition and storage stability problems of sodium hypochlorite solution,a stabilized sodium hypochlorite solution containing 5.0% (mass fraction) active chlorine,8.8% (mass fraction) sodium sulfamate,4.8% (mass fraction) sodium tripolyphosphate,and 2.0% (mass fraction) free sodium hydroxide has been preparated by adding industrial sodium hypochlorite solution into solution of sodium sulfamate and sodium tripolyphosphate.In rapid stability evaluation tests,a stabilized sodium hypochlorite solution was stored for 14 d at 54 ℃ and 12.6% active chlorine was lost and a validity period of 12 months could be predicted.Machanism of stabilization was that an aggregation of molecules of sodium sulfamate and sodium hypochlorite in solution was formed by co-valent effect,so that spontaneous decomposition of sodium hypochlorite solution was inhibited effectively.

Key words: sodium hypochlorite, sulfamic acid；sodium tripolyphosphate；stability