IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Ammonium dihydrogenphosphate with Urea and Water

Components:
   (1) Ammonium dihydrogenphosphate; NH4H2PO4; [7722-76-1]  NIST Chemistry WebBook for detail
   (2) Potassium chloride; KCl; [7747-40-7]  NIST Chemistry WebBook for detail
   (3) Urea; CH4N2O; [57-13-6]  NIST Chemistry WebBook for detail
   (4) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Sarbaev, A.N.; Polyakov, E.V.; Tyunina, M.F.; Polyakova, Z.A.; Ruchkova, A.Kh., Khim. Prom. (Moscow) 1972, 48, 437.

Variables:

   Concentration = Composition, temperature and boiling points at pressures of 20 mm to 760 mm Hg of samples containing a N:P:K ratio equal to 1:1:1.

Prepared By:
   J. Eysseltová

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

Part 1. Solubility in the NH₄H₂PO₄-CO(NH₂)₂-KCl-H₂O system at the ratio N:P:K = 1:1:1.
t/°C	Chemical₁	10² * Mass Fraction w₁	Chemical₂	10² * Mass Fraction w₂^(a)	m₂^(a)	Chemical₃	10² * Mass Fraction w₃^(a)	m₃^(a)	Chemical₄	10² * Mass Fraction w₄^(a)	m₄^(a)	Chemical₅	10² * Mass Fraction w₅^(a)
10	total salt	24.7	CO(NH2)2	4.27	0.945	NH4H2PO4	13.5	1.56	KCl	6.93	1.23	H2O	75.3
20	total salt	29.4	CO(NH2)2	5.08	1.20	NH4H2PO4	16.1	1.98	KCl	8.25	1.57	H2O	70.6
30	total salt	33.0	CO(NH2)2	5.71	1.42	NH4H2PO4	18.0	2.34	KCl	9.26	1.85	H2O	67
40	total salt	36.0	CO(NH2)2	6.23	1.62	NH4H2PO4	19.7	2.67	KCl	10.1	2.12	H2O	64
50	total salt	39.0	CO(NH2)2	6.75	1.84	NH4H2PO4	21.3	3.04	KCl	10.9	2.41	H2O	61
60	total salt	42.3	CO(NH2)2	7.32	2.11	NH4H2PO4	23.1	3.48	KCl	11.9	2.76	H2O	57.7
70	total salt	45.7	CO(NH2)2	7.91	2.42	NH4H2PO4	25.0	4.00	KCl	12.8	3.17	H2O	54.3
80	total salt	49.6	CO(NH2)2	8.58	2.83	NH4H2PO4	27.1	4.67	KCl	13.9	3.70	H2O	50.4
90	total salt	53.5	CO(NH2)2	9.26	3.31	NH4H2PO4	29.2	5.46	KCl	15.0	4.33	H2O	46.5
100	total salt	57.5	CO(NH2)2	9.92	3.96	NH4H2PO4	31.4	6.41	KCl	16.1	5.09	H2O	38.2
110	total salt	61.8	CO(NH2)2	10.7	4.66	NH4H2PO4	33.8	7.68	KCl	17.3	6.09	H2O	38.2
120	total salt	66.7	CO(NH2)2	11.5	5.77	NH4H2PO4	36.4	9.51	KCl	18.7	7.54	H2O	33.3
130	total salt	72.5	CO(NH2)2	12.5	7.59	NH4H2PO4	39.6	12.5	KCl	20.3	9.92	H2O	27.5
140	total salt	79.8	CO(NH2)2	13.8	11.4	NH4H2PO4	43.6	18.8	KCl	22.4	14.9	H2O	20.2

Part 2. Composition and boiling points of saturated solutions in the NH₄H₂PO₄-CO(NH₂)₂-KCl-H₂O system at the ratio N:P:K = 1:1:1.
Boiling Point/°C	Pressure [mm Hg]	Chemical₁	10² * Mass Fraction w₁	Chemical₂	10² * Mass Fraction w₂^(a)	m₂^(a)	Chemical₃	10² * Mass Fraction w₃^(a)	m₃^(a)	Chemical₄	10² * Mass Fraction w₄^(a)	m₄^(a)	Chemical₅	10² * Mass Fraction w₅^(a)
26.7	20	total solute	31.9	CO(NH2)2	5.52	1.35	NH4H2PO4	17.4	2.23	KCl	8.95	1.76	H2O	68.1
41.8	50	total solute	36.6	CO(NH2)2	6.33	1.66	NH4H2PO4	20.0	2.74	KCl	10.3	2.17	H2O	63.4
56.9	100	total solute	41.2	CO(NH2)2	7.13	2.02	NH4H2PO4	22.5	3.33	KCl	11.6	2.64	H2O	58.8
65.7	150	total solute	44.2	CO(NH2)2	7.65	2.28	NH4H2PO4	24.2	3.76	KCl	12.4	2.98	H2O	55.8
73.0	200	total solute	47.0	CO(NH2)2	8.13	2.55	NH4H2PO4	25.7	4.21	KCl	13.2	3.34	H2O	53.0
78.7	250	total solute	49.0	CO(NH2)2	8.48	2.77	NH4H2PO4	26.8	4.56	KCl	13.7	3.62	H2O	51.0
83.6	300	total solute	50.9	CO(NH2)2	8.81	2.99	NH4H2PO4	27.8	4.92	KCl	14.3	3.90	H2O	49.1
87.9	350	total solute	52.6	CO(NH2)2	9.10	3.20	NH4H2PO4	28.7	5.27	KCl	14.8	4.18	H2O	47.4
91.8	400	total solute	54.2	CO(NH2)2	9.38	3.41	NH4H2PO4	29.6	5.62	KCl	15.2	4.45	H2O	45.8
95.4	450	total solute	55.7	CO(NH2)2	9.64	3.62	NH4H2PO4	30.4	5.97	KCl	15.6	4.73	H2O	44.3
98.5	500	total solute	56.9	CO(NH2)2	9.84	3.80	NH4H2PO4	31.1	6.27	KCl	16.0	4.97	H2O	43.1
100.9	550	total solute	57.9	CO(NH2)2	10.0	3.96	NH4H2PO4	31.6	6.53	KCl	16.2	5.18	H2O	42.1
103.6	600	total solute	59.1	CO(NH2)2	10.2	4.16	NH4H2PO4	32.3	6.86	KCl	16.6	5.44	H2O	40.9
105.7	650	total solute	60.0	CO(NH2)2	10.4	4.32	NH4H2PO4	32.8	7.12	KCl	16.8	5.65	H2O	40.0
108.0	700	total solute	61.0	CO(NH2)2	10.6	4.50	NH4H2PO4	33.3	7.43	KCl	17.1	5.89	H2O	39.0
110.6	760	total solute	62.2	CO(NH2)2	10.8	4.74	NH4H2PO4	34.0	7.82	KCl	17.5	6.19	H2O	37.8

Notes:
   Table 1  ^a  These values were calculated by the compiler. The molalities are expressed as mol/kg H₂O.
   Table 2  ^a  These values were calculated by the compiler. The molalities are expressed as mol/kg H₂O.

Method/Apparatus/Procedure:
   A visual polythermic method was used at temperatures below 50 °C. Supersaturation was prevented by seeding. Above 50 °C a synthetic method was used^1-3. The samples were placed in glass ampules and placed in an air thermostat where they were rotated at 3 rpm. They were observed through a glass window in the thermostat. A self-constructed apparatus based on the principle described elsewhere⁴ was used.

Source and Purity of Materials:
   Reagent grade NH₄H₂PO₄ (GOST 6691-67) and urea (GOST 3771-64) and chemically pure KCl (GOST 4234-69) were used.

Estimated Errors:
   Solubility: No information is given.
   Temperature: With the visual-polythermic method the difference between the temperature of dissolution of the last crystal and appearance of the first crystal was less than + 0.5 K. Above 50 °C the temperature had a precision of 0.4 K. No other information is given.

References:
   ¹Alekseev, V.F. Zh. Russ. Fiz.-Khim. Obshch. 1876, 8, 329.
   ²Lebedeva, E.S.; Khodeeva, S.M. Zh. Fiz. Khim. 1961, 35, 2602.
   ³Krichevskiy, I.R.; Khazanova, N.E.; Liushits, L.P. Zh. Fiz. Khim. 1957, 31, 2711.
   ⁴Goroletskiy, Ya; Olevskiy, V.M.; Levitanayte, R.P. Zh. Fiz. Khim. 1964, 38, 2874.