IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Ammonium formate with Formic acid

Components:
   (1) Ammonium formate; NH4CHO2; [540-69-2]  NIST Chemistry WebBook for detail
   (2) Formic acid; CH2O2; [64-18-6]  NIST Chemistry WebBook for detail

Original Measurements:
   Kendall, J.; Adler, H., J. Am. Chem. Soc. 43, 1470 (1921).

Variables:
   Temperature = 239.4 K to 390.5 K

Prepared By:
   T. A. Ageyeva

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

Table 1. The solubility of ammonium formate in formic acid.
t/°C	10⁰ * Mole Fraction₁	Solid Phase(s)^a
8.47	0.0	A
7.0	1.53	A
4.5	3.70	A
0.6	6.28	A
-2.8	8.19	A
-6.9	10.14	A
-12.6	12.43	A
-19.8	14.86	A
-26.9	17.11	A
-33.8	18.95	A
-31.3	20.43	B
-30.0	21.73	B
-29.3	23.33	B
20.4	44.38	C
29.3	46.06	C
37.5	47.87	C
53.1	51.88	C
74.3	59.98	C
89.5	68.23	C
96.5	74.32	C
98.5	76.20	C
103.7	83.46	C
108.5	88.41	C
111.7	91.64	C
117.3	100.0	C

Table 2. The solubility of ammonium formate in formic acid.
Initial Temperature (T_In)/°C	Final Temperature (T_Fin)/°C	10⁰ * Mole Fraction₁	Solid Phase(s)^a
-32.5		23.33	D
-26.0		24.83	D
-23.5		25.41	D
-18.7	-13.7	26.64	D
-14.0	-8.7	27.90	D
	0.7	30.11	D
1.3	10.4	33.25	D
7.4	17.3	36.29	D
11.3	22.2	39.30	D
13.8	24.9	41.90	D
14.3	25.8	42.94	D
15.0		44.38	D

Notes:
   ^a  The solid phases are: A = CH₂O₂; B = NH₄CHO₂•3CH₂O₂; C = NH₄CHO₂; D = NH₄CH₂O₂•CH₂O₂.
   ^b  Denotes equilibrium temperature for unstable NH₄CHO₂.
   ^c  Denotes equilibrium temperature for stable NH₄CHO₂.

Method/Apparatus/Procedure:
   The only information given is that the solubility values were determined by the freezing point method.

Source and Purity of Materials:
   The ammonium salt was prepared by passing NH₃ into 90% formic acid. The product was recrystallized from absolute alcohol and dried over 99% sulfuric acid in a vacuum; m.p.=390.5±0.2 K. The formic acid was prepared by treating a c.p. product with B₂O₃. It was then distilled in vacuo until a product melting above 281.6 K was obtained.

Estimated Errors:
   Solubility: Nothing is specified.
   Temperature: Nothing is specified.