Journal of Chemical and Engineering Data, Vol.52, No.4, 1386-1389, 2007
Phase diagram for the system ammonium oxalate plus hydrogen peroxide plus water at 283.15 k and 293.15 K
The solubility of the ternary system (NH4)(2)C2O4 + 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)(2)C2O4 + H2O2 + H2O system which correspond to (NH4)(2)C2O4 center dot H2O and (NH4)(2)C2O4 center dot H2O2. The compound (NH4)(2)C2O4 center dot H2O2 was further confirmed by Schreinemaker's wet residue method. The hydrate (NH4)(2)C2O4 center dot H2O has a bigger crystallization field than either (NH4)(2)C2O4 center dot H2O2 or the mixture of (NH4)(2)C2O4 center dot H2O and (NH4)(2)C2O4 center dot H2O2. The solubilities of (NH4)(2)C2O4 center dot H2O increased sharply with an increase in the concentration of hydrogen peroxide and increased slightly with increasing temperature.