IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Ammonia with Phosphoric acid and Water

Components:
   (1) Ammonia; NH3; [7664-41-7]  NIST Chemistry WebBook for detail
   (2) Phosphoric acid; H3PO4; [7664-38-2]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Balabanovich, Ya.K.; Orekhov, I.I.; Tereshchenko, L.Ya., Trud. Sev.-Zapad. Politekh. Inst. 1969, 69.

Variables:

   Concentration = Temperature and composition

Prepared By:
   L.V. Chernykh and J. Eysseltová

Experimental Remarks:


Part 1. Definition of the sections:
Section 1 has a mass ratio for H₂O/H₃PO₄ of 9.
Section 2 has a mass ratio for H₂O/H₃PO₄ of 4.
Section 3 has a mass ratio for H₂O/H₃PO₄ of 2.3.
Section 4 has a mass ratio for H₂O/H₃PO₄ of 1.5.

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)

Part 2. Eutectic points having NH₄H₂PO₄ and ice as the equilibrium solid phases.
Solution number	Initial Temperature (T_In)/°C	Final Temperature (T_Fin)/°C	Chemical₁	10² * Mass Fraction w₁	Chemical₂	10² * Mass Fraction w₂	Chemical₃	10² * Mass Fraction w₃	m₃ [mol/kg]	Chemical₄	10² * Mass Fraction w₄	m₄ [mol/kg]	Chemical₅	10² * Mass Fraction w₅
1	-6	-12	NH4H2PO4	16.60	H3PO4	8.29	NH3 (a)	2.46	1.92	H3PO4 (a)	22.43	3.047	H2O (a)	75.11
2	-7	-17	NH4H2PO4	16.60	H3PO4	16.70	NH3 (a)	2.46	2.16	H3PO4 (a)	30.84	4.718	H2O (a)	66.70
3	-14.5	-21	NH4H2PO4	19.35	H3PO4	24.15	NH3 (a)	2.86	2.98	H3PO4 (a)	40.63	7.339	H2O (a)	56.50
4	-25.5	-28	NH4H2PO4	19.35	H3PO4	32.35	NH3 (a)	2.86	3.48	H3PO4 (a)	48.83	10.32	H2O (a)	48.30

Part 3. Solubility of NH₄H₂PO₄ in aqueous solutions of H₃PO₄^a.
Solution number	t/°C	10² * Mass Fraction w₁
1	10	20.99
1	20	26.63
1	30	29.27
1	40	31.50
1	50	35.61
1	60	40.84
1	70	44.6
2	10	23.57
2	20	25.92
2	30	28.69
2	40	31.54
2	50	34.07
2	60	38.11
2	70	41.31
3	10	22.41
3	20	24.99
3	30	30.32
3	40	32.24
3	50	35.9
3	60	38.69
3	70	41.09
4	10	21.09
4	20	26.26
4	30	29.21
4	40	33.12
4	50	36.28
4	60	38.86
4	70	41.19

Part 4. Using the data in Part 3, the compilers have calculated the following values.
Solution number	t/°C	Chemical₁	10² * Mass Fraction w₁	m₁ [mol/kg]	Chemical₂	10² * Mass Fraction w₂	m₂ [mol/kg]	Chemical₃	10² * Mass Fraction w₃
Section 1	10	NH3	3.11	2.57	H3PO4	25.78	3.70	H2O	71.11
Section 1	20	NH3	3.94	3.51	H3PO4	30.02	4.64	H2O	66.03
Section 1	30	NH3	4.33	4.00	H3PO4	32.01	5.13	H2O	63.66
Section 1	40	NH3	4.66	4.44	H3PO4	33.68	5.58	H2O	61.65
Section 1	50	NH3	5.27	5.34	H3PO4	36.78	6.48	H2O	57.94
Section 1	60	NH3	6.05	6.67	H3PO4	40.71	7.80	H2O	53.24
Section 2	10	NH3	3.49	3.35	H3PO4	35.36	5.90	H2O	61.14
Section 2	20	NH3	3.84	3.80	H3PO4	36.90	6.35	H2O	59.26
Section 2	30	NH3	4.25	4.37	H3PO4	38.70	6.92	H2O	57.05
Section 2	40	NH3	4.67	5.01	H3PO4	40.56	7.56	H2O	54.77
Section 2	50	NH3	5.04	5.62	H3PO4	42.21	8.17	H2O	52.74
Section 2	60	NH3	5.64	6.69	H3PO4	44.84	9.24	H2O	49.51
Section 2	70	NH3	6.12	7.65	H3PO4	46.93	10.20	H2O	46.95
Section 3	10	NH3	3.32	3.60	H3PO4	42.60	8.04	H2O	54.08
Section 3	20	NH3	3.70	4.16	H3PO4	44.02	8.59	H2O	52.28
Section 3	30	NH3	4.49	5.43	H3PO4	46.94	9.86	H2O	48.56
Section 3	40	NH3	4.77	5.93	H3PO4	48.00	10.37	H2O	47.23
Section 3	50	NH3	5.31	6.99	H3PO4	50.01	11.42	H2O	44.68
Section 3	60	NH3	5.73	7.87	H3PO4	51.54	12.31	H2O	42.73
Section 3	70	NH3	6.08	8.70	H3PO4	52.86	13.14	H2O	41.06
Section 4	10	NH3	3.12	3.87	H3PO4	49.53	10.67	H2O	47.35
Section 4	20	NH3	3.89	5.16	H3PO4	51.87	11.96	H2O	44.24
Section 4	30	NH3	4.32	5.98	H3PO4	53.20	12.78	H2O	42.47
Section 4	40	NH3	4.90	7.17	H3PO4	54.97	13.98	H2O	40.13
Section 4	50	NH3	5.37	8.25	H3PO4	56.39	15.05	H2O	38.23
Section 4	60	NH3	5.75	9.21	H3PO4	57.56	16.01	H2O	36.68
Section 4	70	NH3	6.10	10.15	H3PO4	58.61	16.95	H2O	35.29


Solution number	t/°C	Chemical₁	10² * Mass Fraction w₁	m₁ [mol/kg]	Chemical₂	10² * Mass Fraction w₂	m₂ [mol/kg]	Chemical₃	10² * Mass Fraction w₃
Section 1	70	NH3	6.60	7.78	H3PO4	43.53	8.91	H2O	49.86

Notes:
   Table 2  ^a  These values were calculated by the compiler.
   Table 2  ^b  Eutectic temperature measured by heating.
   Table 2  ^c  Eutectic temperature measured by cooling
   Table 3  ^a  The solubility values are given as 100w_i

Method/Apparatus/Procedure:
   A visual polythermic method was used. Standard methods of analysis were used, but no specific details are given.

Source and Purity of Materials:
   Chemically pure H₃PO₄ and recrystallized NH₄H₂PO₄ were used.

Estimated Errors:
   Solubility: No information is given.
   Temperature: No information is given.