IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Sodium formate with Acetic acid

Components:
   (1) Acetic acid; C2H4O2; [64-19-7]  NIST Chemistry WebBook for detail
   (2) Sodium formate; NaCHO2; [141-53-7]  NIST Chemistry WebBook for detail

Original Measurements:
   Davidson, A.W.;Ramskill, E.A., J. Am. Chem. Soc. 63, 1221 (1941).

Variables:
   Temperature = 283 K to 526 K

Prepared By:
   T. A. Ageyeva

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

Solubility of sodium formate in acetic acid.
t/°C	10⁰ * Mole Fraction₁	Solid Phase(s)^a
16.60	0	A
16.15	0.54	A
15.60	1.33	A
14.25	2.96	A
13.50	3.74	A
12.75	4.78	A
11.80	5.79	A
10.60	7.27	A
9.70	8.14	A
14.55	8.75	B
17.70	9.24	B
27.10	11.08	B
32.25	12.22	B
40.10	14.61	B
44.35	15.73	B
53.0	18.18	B
56.2	19.76	B
63.1	22.36	B
66.5	26.34	B
68.2	28.32	B
69.0	30.42	B
69.2	32.17	B
69.2	32.80	B
80.0	33.09	C
83.0	33.51	C
87.0	33.98	C
109	35.24	C
114	35.73	C
171	46.46	C
173	49.81	C
179	50.17	D
215	60.48	D
227	68.93	D
253	100	D

Notes:
   ^a  The solid phases are: A = C₂H₄O₂; B = NaCHO₂•2C₂H₄O₂; C = NaCHO₂•C₂H₄O₂; D = NaCHO₂.

Method/Apparatus/Procedure:
   The solubility of sodium formate in acetic acid was determined by the freezing point method.¹ Samples of solid were obtained by means of crystallization between porous tiles and analyzed acidimetrically, the acidity being calculated as acetic acid.

Source and Purity of Materials:
   Sodium formate was prepared from hydrated samples by means of recrystallization from water and drying for 5 days at 413 K; m.p. = 526.2 K. Anhydrous acetic acid was prepared as described elsewhere.^2,3.

Estimated Errors:

   Temperature: Precision of temperature was about 0.1 K for temperature below 323 K; 0.2 K between 323 and 373 K; and 1 K above 373 K.

References:
   ¹A. W. Davidson and W. H. McAllister, J. Am. Chem. S. 52, 507 (1930).
   ²A. W. Davidson and W. Chappell, J. Am. Chem. S. 55, 3531 (1933).
   ³A. W. Davidson and W. Chappell, J. Am. Chem. S. 55, 4524 (1933).