IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Pentachlorophenol with Ammonium Chloride and Water

Components:
   (1) Ammonium Chloride; NH4Cl; [12125-02-9]  NIST Chemistry WebBook for detail
   (2) Pentachlorophenol; C6HCl5O; [87-86-5]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Toyota, H.; Kuwahara, M., Nippon Dojohiryogaku Zasshi 1967, 38(2,3), 93-97.

Variables:
   Temperature = 27 °C
pH = pH
   Concentration = Concentrations of NH₄Cl

Prepared By:
   H. Ohtaki

Experimental Remarks:

   COMMENTS AND/OR ADDITIONAL DATA:

Solubilities of pentachlorophenol in water versus hydrogen ion activity, in the absence of KCl, at 27 °C were measured and calculated. The stoichiometric amounts of dissolved pentachlorophenol were calculated from mass balance based upon incomplete dissociation. The dissociation constant was given as K_p = [C₆CL₅O ^-] [H ⁺] / [C₆CL₅OH] = 3.2 x 10^-5 mol/dm³. This value together with the activity of the hydrogen ion, {H ⁺}, as determined from pH measurements was incorporated in an equation for calculating the solubility:

S = [1.796 x 10^-6/{H ⁺}0.170] [1 + 3.2 x 10^-5/{H ⁺}]

Observed and calculated values reported:

5.0 6.0 7.0

10⁵mol(1)/dm³ 10⁴mol(1)/dm³ 10³mol(1)/dm³

Observed value:4.05 6.05 8.85

Calculated value: 5.34 6.20 8.90

Experimental Data: (Notes on the Nomenclature)


t/°C	10² * g₁/V₂ [g dm**-3]	10⁵ * Concentration c₁ [mol dm**-3]	Concent. c₁ Note	Concentration c₂ [mol dm**-3]	10⁷ * Mole Fraction x₁	x₁ Note	Initial pH	pH	pH Note
27	0.8390	3.15	b	1.0	5.690	a,c	5	5.12	d
27	1.377	5.17	b	0.50	9.335	a,c	5	5.20	d
27	3.3161	12.45	b	0.05	22.472	a,c	5	5.41	d
27	3.0657	11.51	b	0.0	20.774	a,c	5	5.35	d


t/°C	10² * g₁/V₂ [g dm**-3]	10⁴ * Concentration c₁ [mol dm**-3]	Concent. c₁ Note	Concentration c₂ [mol dm**-3]	10⁶ * Mole Fraction x₁	x₁ Note	Initial pH	pH	pH Note
27	6.153	2.31	b	0.05	4.170	a,c	5.5	5.73	d


t/°C	10¹ * g₁/V₂ [g dm**-3]	10⁴ * Concentration c₁ [mol dm**-3]	Concent. c₁ Note	Concentration c₂ [mol dm**-3]	10⁵ * Mole Fraction x₁	x₁ Note	Initial pH	pH	pH Note
27	1.489	5.59	b	1.0	1.010	a,c	6	6.01	d
27	1.345	5.05	b	0.50	0.9120	a,c	6	6.05	d
27	2.9645	11.13	b	0.30	2.0099	a,c	6	6.19	d
27	2.650	9.95	b	0.20	1.797	a,c	6	6.14	d
27	0.5993	2.25	b	0.0	0.4061	a,c	6	5.70	d


t/°C	10¹ * g₁/V₂ [g dm**-3]	10³ * Concentration c₁ [mol dm**-3]	Concent. c₁ Note	Concentration c₂ [mol dm**-3]	10⁵ * Mole Fraction x₁	x₁ Note	Initial pH	pH	pH Note
27	2.352	0.883	b	1.0	1.595	a,c	6.5	6.46	d
27	3.9819	1.495	b	0.50	2.7005	a,c	6.5	6.50	d
27	5.966	2.24	b	0.10	4.045	a,c	6.5	6.40	d
27	6.233	2.34	b	0.0	4.226	a,c	6.5	6.52	d


t/°C	10¹ * g₁/V₂ [g dm**-3]	10³ * Concentration c₁ [mol dm**-3]	Concent. c₁ Note	Concentration c₂ [mol dm**-3]	10⁵ * Mole Fraction x₁	x₁ Note	Initial pH	pH	pH Note
27	2.9432	1.105	b	1.0	1.9967	a,c	7.0	6.97	d
27	5.114	1.92	b	0.50	3.469	a,c	7.0	6.98	d
27	7.777	2.92	b	0.30	5.275	a,c	7.0	7.03	d
27	8.736	3.28	b	0.20	5.926	a,c	7.0	7.10	d
27	11.13	4.18	b	0.10	7.553	a,c	7.0	6.86	d
27	14.76	5.54	b	0.05	10.01	a,c	7.0	6.92	d
27	20.40	7.66	b	0.0	13.85	a,c	7.0	6.92	d


t/°C	g₁/V₂ [g dm**-3]	10³ * Concentration c₁ [mol dm**-3]	Concent. c₁ Note	Concentration c₂ [mol dm**-3]	10⁴ * Mole Fraction x₁	x₁ Note	Initial pH	pH	pH Note
27	1.675	6.29	b	.10	1.137	a,c	7.5	7.50	d


t/°C	g₁/V₂ [g dm**-3]	10³ * Concentration c₁ [mol dm**-3]	Concent. c₁ Note	Concentration c₂ [mol dm**-3]	10⁵ * Mole Fraction x₁	x₁ Note	Initial pH	pH	pH Note
27	0.3276	1.23	b	1.0	2.223	a,c	8	8.02	d
27	0.5780	2.17	b	0.50	3.920	a,c	8	8.00	d
27	0.6339	2.38	b	0.30	4.299	a,c	8	8.05	d
27	1.247	4.68	b	0.20	8.458	a,c	8	8.01	d
27	1.851	6.95	b	0.10	12.57	a,c	8	8.01	d
27	2.903	10.9	b	0.05	19.73	a,c	8	7.95	d
27	19.39	72.8	b	0.0	133.8	a,c	8	7.80	d

Notes:
   ^a  Calculated by F. W. Getzen.
   ^b  Reported.
   ^c  Calculated mole fraction based upon complete dissociation of NH₄Cl.
   ^d  pH value of solution equilibriated with precipitate.

Method/Apparatus/Procedure:
   Pentachlorophenol and various amounts of NaOH and NH₄Cl were dissolved in water at 27°C and the solutions were left for 3 days with occasional stirring (once a day for 1 hour). Then, the undissolved pentachlorophenol was filtered off and the pH values of the filterates were measured with a glass electrode. To each aliquot of the solutions was added hydrochloric acid to maintain their pH less than 3. The precipitates which resulted were aged and weighed.

Source and Purity of Materials:
   (1) Nothing specified.

Estimated Errors:
   Solubility: No estimation was given for errors in the solubility measurements. However, the reported values of S/S° (S the solubility of pentachlorophenol in KCI solutions and S° its solubility in pure water) do not fall on a single smooth curve, but rather spread. T