Compilation - Ammonium dihydrogenphosphate with Diammonium hydrogenphosphate, Urea, Potassium chloride and Water (IUPAC SDS Volume 66)
SDS Volume (2993)
Volume 66. Ammonium Phosphates, p None
Original Measurements
Slack, A. V.; Hatfield, J. D.; Shaffer, H. B.; Driskell, J. C.; J. Agr. Food Chem. 1959, 7, 404.
Variables:
Temperature and composition.
Prepared by:
Method/Apparatus/Procedure:
The solubility was determined by a polythermal method. The solutions were cooled until crystallization occurred and then warmed (2 °C per hour) with continuous stirring until the last crystals disappeared. The crystalline phases were identified petrographically.
Source and Purity of Materials:
- All the salts used were reagent grade. The water was deionized.
Estimated Errors:
Mass concentration (m/v) (1): The standard deviation of equation [1] from the measured values was 0.12% in plant nutrient.
Components:
- Ammonium dihydrogenphosphate, $\ce{ NH4H2PO4 }$; [7722-76-1] NIST WebBook
- Diammonium hydrogenphosphate, $\ce{ (NH4)2HPO4 }$; [7783-28-0] NIST WebBook
- Urea, $\ce{ CH4N2O }$; [57-13-6] NIST WebBook
- Potassium chloride, $\ce{ KCl }$; [7447-40-7] NIST WebBook
- Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
Solubility isotherms at 0°C are given only graphically as contours of constant plant nutrient content in the saturated solutions with the nutrient ratios as the variables. Numerically, the data are expressed by Eq. [1]:
y = a + bt [1]
where y is the percent total plant nutrient (% N + %P2O5 + %K2O) in the saturated solution at temperature t (°C), and a and b are constants for each combination of nutrient ratio and ammoniation level. These constants are given in the table below.
Mol ratio NH3/H3PO4
| Nutrient ratio | $R_{1/2}$ | 1st coef. | 2nd coef. ($\pu{^{\circ}C-1}$) |
|---|---|---|---|
| 1-3-0 | 1.5 | 34.6 | 0.342 |
| 1-3-0 | 1.6 | 36.9 | 0.141 |
| 1-3-0 | 1.7 | 34.1 | 0.119 |
| 1-2-0 | 1.5 | 35.8 | 0.244 |
| 1-2-0 | 1.6 | 34.7 | 0.123 |
| 1-2-0 | 1.7 | 32.1 | 0.119 |
| 1-1-0 | 1.5 | 32.7 | 0.241 |
| 1-1-0 | 1.6 | 31.8 | 0.082 |
| 1-1-0 | 1.7 | 29.1 | 0.119 |
| 1-1-0 | 1.5 | 34.6 | 0.065 |
| 2-1-0 | 1.5 | 26.2 | 0.283 |
| 2-1-0 | 1.6 | 26.1 | 0.281 |
| 2-1-0 | 1.7 | 26.1 | 0.262 |
| 2-1-0 | 1.6 | 30.3 | 0.071 |
| 2-1-0 | 1.6 | 28.6 | 0.070 |
| 1-3-1 | 1.5 | 31.2 | 0.233 |
| 1-3-1 | 1.6 | 34.9 | 0.133 |
| 1-3-1 | 1.7 | 32.1 | 0.115 |
| 1-2-1 | 1.5 | 28.2 | 0.245 |
| 1-2-1 | 1.6 | 32.5 | 0.130 |
| 1-2-1 | 1.7 | 31.3 | 0.117 |
| 1-1-1 | 1.5 | 25.9 | 0.156 |
| 1-1-1 | 1.6 | 27.6 | 0.155 |
| 1-1-1 | 1.7 | 27.9 | 0.131 |
| 2-1-2 | 1.5 | 25.2 | 0.118 |
| 2-1-2 | 1.6 | 25.2 | 0.121 |
| 2-1-2 | 1.7 | 25.2 | 0.118 |
| 1-3-3 | 1.5 | 24.7 | 0.138 |
| 1-3-3 | 1.6 | 24.8 | 0.135 |
| 1-3-3 | 1.7 | 24.5 | 0.139 |
| 1-2-3 | 1.5 | 22.7 | 0.124 |
| 1-2-3 | 1.6 | 22.6 | 0.134 |
| 1-2-3 | 1.7 | 22.6 | 0.129 |
| 1-1-3 | 1.5 | 20.0 | 0.121 |
| 1-1-3 | 1.6 | 19.9 | 0.125 |
| 1-1-3 | 1.7 | 20.0 | 0.121 |
| 2-1-6 | 1.5 | 18.3 | 0.121 |
| 2-1-6 | 1.6 | 18.5 | 0.117 |
| 2-1-6 | 1.7 | 18.5 | 0.117 |
(a) The nutrient ratio is the weight ratio N:P2O5·K2O. Symbol solid phase.
(b) NH4H2PO4
(c) (NH4)2HPO4
(d) CO(NH2)2 (t<10.8°C)
(e) (NH4)2HPO4 (t>-1.5°C), urea crystallized below -1.5°C.
(f) (NH4)2HPO4 (t>10.8°C)
(g) CO(NH2)2
(h) CO(NH2)2 (t>20.0°C)
(i) CO(NH2)2(t<12.9°C)
(j) (NH4)2HPO4 (t>20.0°C)
(k) (NH4)2HPO4 (t>12.9°C)
(m) KCl
