Solid–Liquid Phase Equilibria of (Ca(H2PO2)2 + H2O), (Ca(H2PO2)2 + CaCl2 + H2O), and (Ca(H2PO2)2 + NaH2PO2 + H2O) Systems

详细信息    查看全文

• 作者：Jian-nan Yin ; Xin-ying Shi ; Huan ZhouJing-jing Tang ; Ya-ping Dai ; Xiao-qin Bai
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2017
• 出版时间：February 9, 2017
• 年：2017
• 卷：62
• 期：2
• 页码：744-751
• 全文大小：522K
• ISSN：1520-5134

文摘

Fine calcium hypophosphite can be synthesized by sodium hypophosphite and calcium chloride via the replacement reaction, and sodium hypophosphite can be synthesized from phosphorus via the intermediate of Ca(H₂PO₂)_2. Both processes involve the interactive quaternary system of (Ca²⁺ + Na⁺)//(Cl^– + (H₂PO₂)⁻ + H₂O) and its subsystems. In this study, the (solid + liquid) phase diagrams of the (Ca(H₂PO₂)₂ + H₂O) binary system from freezing to boiling point at normal pressure, and (Ca(H₂PO₂)₂ + CaCl₂ + H₂O), (Ca(H₂PO₂)₂ + NaH₂PO₂ + H₂O) ternary systems at 273.15 K were experimentally determined via the classical isothermal solubility equilibrium method. It was found that (1) one anhydrous salt of Ca(H₂PO₂)₂ occurs in (Ca(H₂PO₂)₂ + H₂O) binary systems with temperatures ranging from freezing to boiling points, (2) two solid salts of Ca(H₂PO₂)₂ and CaCl₂·6H₂O exist in the (Ca(H₂PO₂)₂ + CaCl₂ + H₂O) system, and (3) Ca(H₂PO₂)₂, NaH₂PO₂·H₂O and one incompatible double salt of NaCa(H₂PO₂)₃ exist in the (Ca(H₂PO₂)₂ + NaH₂PO₂ + H₂O) system, and NaCa(H₂PO₂)₃ has very low solubility and occupies a large solid field in the ternary system.