Compilation - Ammonium dihydrogenphosphate with Ammonium nitrate, Urea nitrate, Urea phosphate and Water (IUPAC SDS Volume 66)

SDS Volume (2858)

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:

J. Eysseltová

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 $\ce{NH3}$. Nitrate was determined gravimetrically with Nitron. The sum of $\ce{NH4^{+}}$ and urea was determined by the Kjeldahl method and the concentration of urea salts was determined by acidimetric titration with a METROHM potentiograph.

Source and Purity of Materials:
  1. The ammonium salts were recrystallized before use. The urea salts were synthesized from urea and an equivalent amount of the respective acid and recrystallized several times.
Estimated Errors:

Ambient temperature: No information given.

Components:
  1. Ammonium dihydrogenphosphate, $\ce{ NH4H2PO4 }$; [7722-76-1] NIST WebBook
  2. Ammonium nitrate, $\ce{ NH4NO3 }$; [6484-52-2] NIST WebBook
  3. Urea nitrate, $\ce{ CO(NH2)2.HNO3 }$; [124-47-0] NIST WebBook
  4. Urea phosphate, $\ce{ CO(NH2)2.H3PO4 }$; [4861-19-2] NIST WebBook
  5. Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
Composition of invariant points in the NH4H2PO4-2.HNO3-CO(NH2)2·H3PO4-H2O system at 20 and 40°C
$T$ (°C) 100w1 100w2 100w3 100w4 m1 (mol/kg) m2 (mol/kg) m3 (mol/kg) Phase (s) ()
20 15.2614.9231.5938.23 3.2452.4697.183A + B + C
40 19.5320.7334.3625.38 6.2555.16811.77A + B + C

(a) The molalities were calculated by the compiler and are expressed as mol kg-1.

(b) The solid phases are: A = CO(NH2)2·HNO3; B = CO(NH2)2·H3PO4; C = NH4H2PO4; D = NH4NO3.

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