ABSTRACT

Physico-chemical properties of the binary system NaHSO4 KHSO4 were studied by calorimetry and conductivity. The enthalpy of mixing has been measured at 505K in the full composition range and the phase diagram calculated. The phase diagram has also been constructed from phase transition temperatures obtained by conductivity for 10 different compositions and by differential thermal analysis. The phase diagram is of the simple eutectic type, where the eutectic is found to have the composition X(KHSO4) = 0.44 (melting point 406 K). The conductivities in the liquid region have been fitted to polynomials of the form .(X) = A(X) + B(X)(T-Tm) +C(X)(T-Tm)2, where Tm is the intermediate temperature of the measured temperature range and X, the mole fraction of KHSO4. The possible role of this binary system as a catalyst solvent is also discussed.

Compounds

#	Formula	Name
1	HKO4S	hydrogen potassium sulfate
2	HNaO4S	sulfuric acid, monosodium salt

Datasets

The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type	Compound-#	Property	Variable	Constraint	Phase	Method	#Points
POMD	1	Solid-liquid equilibrium temperature, K ; Crystal 1	Pressure, kPa; Crystal 1		Crystal 1 Liquid	OTHER::sMethod:Conductivity measurements	1
POMD	2	Solid-liquid equilibrium temperature, K ; Crystal	Pressure, kPa; Crystal		Crystal Liquid	Conductivity measurements	1
POMD	1 2	Eutectic temperature, K ; Crystal - 1			Crystal - 1 Crystal - 2 Liquid Air at 1 atmosphere	PHASDIA:	1
POMD	1 2	Eutectic composition: mole fraction - 1 ; Crystal - 1			Crystal - 1 Crystal - 2 Liquid Air at 1 atmosphere	Derived from phase diagram analysis	1
POMD	1 2	Excess molar enthalpy (molar enthalpy of mixing), kJ/mol ; Liquid	Mole fraction - 1; Liquid	Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Calvet calorimetry	7
POMD	1 2	Solid-liquid equilibrium temperature, K ; Liquid	Mole fraction - 1; Liquid	Pressure, kPa; Liquid	Liquid Crystal - 2	Conductivity measurements	5
POMD	1 2	Solid-liquid equilibrium temperature, K ; Liquid	Mole fraction - 1; Liquid	Pressure, kPa; Liquid	Liquid Crystal 2 - 1	Conductivity measurements	3
POMD	1 2	Solid-liquid equilibrium temperature, K ; Liquid	Mole fraction - 1; Liquid	Pressure, kPa; Liquid	Liquid Crystal 1 - 1	Conductivity measurements	2

Thermodynamics Research Center / ThermoML | Thermochimica Acta

Conductivity, calorimetry and phase diagram of the NaHSO4 KHSO4 system

Hamma, H., Rasmussen, S. B., Rogez, J., Alaoui-Elbelghiti, M., Eriksen, K. M., Fehrmann, R.

ABSTRACT