IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Potassium formate with Formic acid and Water

Components:
   (1) Potassium formate; KCHO2; [590-29-4]  NIST Chemistry WebBook for detail
   (2) Formic acid; CH2O2; [64-18-6]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Sas, T.M.; Rodina,G.L.; Velikodnyn, Yu. A., Tr. IREA Moscow Ser. Reagents and specially pure substances 42, 168 (1980).

Variables:

   Concentration = Composition at 298.2 K and 323.2 K

Prepared By:
   T. A. Ageyeva

Experimental Remarks:

   Note: The data for 323.2 K are given only in graphical form.

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

Solubility in the KCHO₂-CH₂O₂-H₂O system at 298.2 K.
Chemical₁	Mass Fraction w₁^a	10⁰ * Mole Fraction₁^a	Chemical₂	Mass Fraction w₂	Mole Fraction₂^a	Chemical₃	Mass Fraction w₃	Mole Fraction₃^a	Solid Phase(s)^b
KCHO2	27.9	17.4	CH2O2	72.0	82.3	H2O	0.1	0.3	A
KCHO2	40.5	25.8	CH2O2	56.7	65.9	H2O	2.8	8.3	A
KCHO2	40.5	20.8	CH2O2	43.4	43.7	H2O	16.1	38.6	A
KCHO2	37.6	17.7	CH2O2	40.8	35.0	H2O	21.6	47.3	A
KCHO2	34.6	14.2	CH2O2	34.0	25.5	H2O	31.4	60.2	A
KCHO2	44.8	19.9	CH2O2	27.2	22.1	H2O	28.0	58.0	A
KCHO2	45.4	19.7	CH2O2	24.6	19.5	H2O	30.0	60.8	A
KCHO2	56.5	25.7	CH2O2	13.85	11.5	H2O	29.65	62.9	B
KCHO2	60.7	28.2	CH2O2	10.3	8.76	H2O	29.0	63.0	B
KCHO2	76.2	43.2	CH2O2	3.85	3.99	H2O	19.95	52.8	C
KCHO2	78.4	43.7	CH2O2	0.0	0.0	H2O	21.6	56.3	C

Notes:
   ^a  These values were calculated by the compiler.
   ^b  The solid phases are: A = KCHO₂•CH₂O2; B = KCHO₂•CH₂O₂•0.5H₂O; C = KCHO₂.

Method/Apparatus/Procedure:
   The isothermal method was used ¹. The formic acid content was determined by titration with 0.1 N NaOH using phenolphthalein as indicator. The KCHO₂ content was determined by titration with NaOH after passing the weighed sample through a chromatographic column. The water content was calculated by difference. The solid phase was identified by chemical, thermogravimetric, gas chromatographic and x-ray methods.

Source and Purity of Materials:
   Temperature: No information is given.

Estimated Errors:
   Solubility: ± 0.5 mass %. Nothing else is specified.
   Temperature: No information is given.

References:
   ¹ D. F. Othmer and P. E. Tobias, Ind. Eng. Chem. 34, 690 (1971).