Rong-Rong Li

Phase Diagram for the System Ammonium Oxalate + Hydrogen Peroxide + Water at 283.15 K and 293.15 K

The solubility of the ternary system (NH4)2C2O4 + H2O2 + H2O was determined experimentally at 283.15 K and 293.15 K, and the phase diagrams for the system were constructed. In addition, the density of the saturated aqueous solution was measured. The experimental results showed that, at 283.15 K and 293.15 K, two solid phases were formed in the ternary (NH4)2C2O4 + H2O2 + H2O system which correspond to (NH4)2C2O4·H2O and (NH4)2C2O4·H2O2. The compound (NH4)2C2O4·H2O2 was further confirmed by Schreinemakers wet residue method. The hydrate (NH4)2C2O4·H2O has a bigger crystallization field than either (NH4)2C2O4·H2O2 or the mixture of (NH4)2C2O4·H2O and (NH4)2C2O4·H2O2. The solubilities of (NH4)2C2O4·H2O increased sharply with an increase in the concentration of hydrogen peroxide and increased slightly with increasing temperature.

Solubility and Phase Diagram for the Ternary Sodium Oxalate + Hydrogen Peroxide + Water System at (283.15 and 293.15) K

In this investigation, the mutual solubilities for the ternary Na2C2O4 + H2O2 + H2O system were determined at (283.15 and 293.15) K. The phase diagrams of the system were constructed based on the measured solubility. The compound Na2C2O4·H2O2 was confirmed by Schreinemakers wet residue method. In addition, the density of the system was obtained. At (283.15 and 293.15) K, two solid phases were formed in the ternary Na2C2O4 + H2O2 + H2O system, which corresponded to Na2C2O4 and Na2C2O4·H2O2. The phase diagrams of the ternary system were similar at different temperatures; the solubilities of Na2C2O4 and Na2C2O4·H2O2 in water increased slightly with increasing temperature. The crystalline region of the compound Na2C2O4·H2O2 decreased as the temperature increased, the temperature having little effect on the yield of Na2C2O4·H2O2.