ABSTRACT

For the first time the solution enthalpies of crystalline phosphonic acid (H3PO3) in N, N-dimethylformamide (DMF) and dilution enthalpies of the acid solutions in DMF (H3PO3 concentrations: x2 less than 0.781 molar fraction or m less than 49 mol/kg) in pure DMF have been measured at T = (298.15, 308.15, 318.15, and 328.5) K. The temperature dependence of the heat capacity of crystalline H3PO3 was obtained also for the first time. The standard solution enthalpies of H3PO3 in DMF have been calculated at different temperatures according to two different models considering the phosphonic acid either as a weak electrolyte dissociating by the first stage or as a non-electrolyte able to form dimmers. A number of thermodynamic properties have been evaluated.

Compounds

#	Formula	Name
1	H3O3P	phosphonic acid
2	C3H7NO	dimethylformamide

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	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Small sample (50 mg) DSC	86
POMD	2 1	Molar enthalpy of solution, kJ/mol ; Liquid	Temperature, K; Liquid Molality, mol/kg - 1; Liquid	Pressure, kPa; Liquid	Liquid	ISOPERIBOL	33
POMD	2 1	Molar enthalpy of dilution, kJ/mol ; Liquid	Temperature, K; Liquid Initial molality of solute, mol/kg; Liquid Final molality of solute, mol/kg; Liquid	Pressure, kPa; Liquid	Liquid	ISOPERIBOL	91

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Thermochemical investigation of the (phosphonic acid + N,N-dimethylformamide) system at T = (298.15 to 328.15) K

Manin, N. G., Fadeeva, Y. A., Safonova, L. P.

ABSTRACT