Phase Equilibria and Solubility Diagram in the Ternary System Sodium Hypochlorite – potassium Chlorate – water
S. A. Niyozov *
Department of Chemical Technology, Bukhara State Technical University, Bukhara, Uzbekistan.
F. E. Umirov
Department of Chemical Technology, Navoi State University of Mining and Technologies, Navoiy, Uzbekistan.
R. A. Makhmudov
Department of Chemical Technology, Bukhara State Technical University, Bukhara, Uzbekistan.
G. R. Nomozova
Department of Chemical Technology, Navoi State University of Mining and Technologies, Navoiy, Uzbekistan.
U. F. Umirov
Department of Life Safety, Navoi State University of Mining and Technology, Navoiy, Uzbekistan.
*Author to whom correspondence should be addressed.
Abstract
Phase equilibria and solubility in the NaClO–KClO₃–H₂O ternary system were investigated over the temperature range from −21 to +18 °C using the visual-polythermal method. Based on experimental data obtained for the boundary binary systems and five internal sections, a complete polythermal solubility diagram was constructed. The diagram reveals the crystallization fields of ice, potassium chlorate, sodium chloride, sodium hypochlorite pentahydrate (NaClO•5H₂O), sodium hypochlorite sesquihydrate (NaClO•2.5H₂O), and anhydrous NaClO. It was established that the system belongs to a simple eutectic type, with no formation of new chemical compounds or solid solutions within the investigated range. A pronounced salting-out effect of sodium hypochlorite on potassium chlorate was observed, leading to a significant decrease in KClO₃ solubility with increasing NaClO concentration. The obtained results provide a physicochemical basis for optimizing crystallization processes and developing efficient chlorate-based defoliant formulations.
Keywords: Sodium hypochlorite, potassium chlorate, NaClO–KClO₃–H₂O system, polythermal method, phase equilibria, solubility diagram, defoliant.