SDS Volume (3016)
Volume 66. Ammonium Phosphates, p None
Original Measurements
Kümmel, R.; Fahsl, R.; Z. Anorg. Allg. Chem. 1973, 402, 305.
Variables:
Room Temp: Composition at 20 and 40 °C
Prepared by:
Method/Apparatus/Procedure:
Mixtures of the components were stirred vigorously and allowed to equilibrate for 15 hrs to 25 hrs. The equilibrium was checked by repeated analysis of the liquid phase. $\ce{PO4^{3-}}$ content was determined by precipitation titration with $\ce{La(NO3)3}$ using Chromazurol S as indicator; $\ce{NH4^{+}}$ was determined, after removal of phosphate ions, with the aid of anion exchange resin by formol tritration. Urea was determined gravimetrically as dixanthedrylurea or after enzyme decomposition as $\ce{NH3}$. The composition of the solid phases was determined by the method of Schreinemakers.
Source and Purity of Materials:
- The ammonium phosphate was recrystallized several times before use. The urea phosphate was synthesized from urea and an equivalent amount of phosphoric acid and recrystallized several times.
Estimated Errors:
Ambient temperature: The temperature was kept constant to within ±0.05 K.
Mass concentration (m/v) (1): No information is given.
Components:
- Ammonium dihydrogenphosphate, $\ce{ NH4H2PO4 }$; [7722-76-1] NIST WebBook
- Urea phosphate, $\ce{ CO(NH2)2.H3PO4 }$; [4861-19-2] NIST WebBook
- Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
Solubility isotherms in the NH4H2PO4-CO(NH2)2·H3PO4-H2O system.
| $T$ (°C) | 100w1 | 100w2 | 100w3 | m1 (mol/kg) | m2 (mol/kg) | Phase (s) () | ρ (g/cm3) |
|---|---|---|---|---|---|---|---|
| 20 | 44.35 | 9.08 | 46.57 | 6.03 | 1.69 | A | 1.2833 |
| 20 | 41.05 | 15.21 | 43.74 | 5.94 | 3.02 | A | 1.3062 |
| 20 | 38.59 | 22.46 | 38.95 | 6.27 | 5.01 | A + B | 1.3409 |
| 20 | 28.78 | 24.24 | 46.98 | 3.88 | 4.49 | B | 1.2877 |
| 20 | 16.26 | 24.60 | 59.14 | 1.74 | 3.62 | B | 1.2255 |
| 20 | 5.63 | 25.40 | 68.97 | 0.516 | 3.20 | B | 1.1737 |
| 20 | 0.000 | 25.50 | 74.50 | 0.000 | 2.98 | B | 1.1518 |
| 40 | 58.94 | 6.91 | 34.15 | 10.92 | 1.76 | A | |
| 40 | 55.05 | 13.31 | 31.64 | 11.01 | 3.66 | A | |
| 40 | 44.35 | 28.06 | 27.59 | 10.17 | 8.84 | A + B | |
| 40 | 35.22 | 28.70 | 36.08 | 6.18 | 6.91 | B | |
| 40 | 23.39 | 30.67 | 45.94 | 3.22 | 5.80 | B | |
| 40 | 11.78 | 33.01 | 55.21 | 1.35 | 5.20 | B | |
| 40 | 0.000 | 36.20 | 63.80 | 0.000 | 4.93 | B |
(a) These values were calculated by the compiler.
(b) The solid phases are: A = CO(NH2)2·H3PO4; B = NH4H2PO4.
