ABSTRACT

Starting from ten eutectic binary phase diagrams, the heat absorbed to melt completely a binary mixture from its solid state was plotted as a function of the mole fraction of one of the two components of the system. Surprisingly, a linear relationship was found for all the studied systems. The extrapolated total heat values at pure component composition (i.e. x = 0 and x = 1) obtained via the heat capacity experimentally determined for each compound were interpreted as the melting enthalpies of the pure components at the eutectic temperature, for each binary system. A mathematical model is proposed that takes into account an ideal liquid state and an enthalpy in the liquid state independent of the temperature.

Compounds

#	Formula	Name
1	C14H22N2O	2-(diethylamino)-N-(2,6-dimethylphenyl)acetamide
2	C10H20O	L-menthol
3	C13H18O2	(S)-2-(4-isobutylphenyl)propanoic acid
4	C13H18O2	ibuprofen
5	C13H10O3	phenyl salicylate
6	C18H36O2	octadecanoic acid
7	C8H9NO2	N-acetyl-p-aminophenol
8	C10H16O	d-camphor
9	C10H16O	1,7,7-trimethylbicyclo[2.2.1]-2-heptanone

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 saturation pressure, J/K/mol ; Crystal	Temperature, K; Crystal		Crystal Gas	Small sample (50 mg) DSC	9
POMD	1	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid		Liquid Gas	Small sample (50 mg) DSC	9
POMD	2	Molar heat capacity at saturation pressure, J/K/mol ; Crystal 1	Temperature, K; Crystal 1		Crystal 1 Gas	Small sample (50 mg) DSC	10
POMD	2	Molar heat capacity at saturation pressure, J/K/mol ; Metastable crystal	Temperature, K; Metastable crystal		Metastable crystal Gas	Small sample (50 mg) DSC	9
POMD	2	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid		Liquid Gas	Small sample (50 mg) DSC	9
POMD	3	Molar heat capacity at saturation pressure, J/K/mol ; Crystal	Temperature, K; Crystal		Crystal Gas	Small sample (50 mg) DSC	9
POMD	3	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid		Liquid Gas	Small sample (50 mg) DSC	10
POMD	4	Molar heat capacity at saturation pressure, J/K/mol ; Crystal	Temperature, K; Crystal		Crystal Gas	Small sample (50 mg) DSC	10
POMD	4	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid		Liquid Gas	Small sample (50 mg) DSC	10
POMD	5	Molar heat capacity at saturation pressure, J/K/mol ; Crystal	Temperature, K; Crystal		Crystal Gas	Small sample (50 mg) DSC	9
POMD	5	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid		Liquid Gas	Small sample (50 mg) DSC	9
POMD	6	Molar heat capacity at saturation pressure, J/K/mol ; Crystal	Temperature, K; Crystal		Crystal Gas	Small sample (50 mg) DSC	10
POMD	6	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid		Liquid Gas	Small sample (50 mg) DSC	10
POMD	7	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid		Liquid Gas	Small sample (50 mg) DSC	10
POMD	7	Molar heat capacity at saturation pressure, J/K/mol ; Crystal	Temperature, K; Crystal		Crystal Gas	Small sample (50 mg) DSC	10
POMD	8	Molar heat capacity at saturation pressure, J/K/mol ; Crystal 2	Temperature, K; Crystal 2		Crystal 2 Gas	Small sample (50 mg) DSC	10
POMD	8	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid		Liquid Gas	Small sample (50 mg) DSC	8
POMD	9	Molar heat capacity at saturation pressure, J/K/mol ; Crystal 2	Temperature, K; Crystal 2		Crystal 2 Gas	Small sample (50 mg) DSC	10
POMD	9	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid		Liquid Gas	Small sample (50 mg) DSC	10
POMD	1 2	Molar heat capacity at saturation pressure, J/K/mol ; Crystal of intercomponent compound 1	Temperature, K; Crystal of intercomponent compound 1	Mole fraction - 1; Crystal of intercomponent compound 1	Crystal of intercomponent compound 1 Gas	Small sample (50 mg) DSC	10
POMD	1 2	Molar heat capacity at saturation pressure, J/K/mol ; Liquid	Temperature, K; Liquid	Mole fraction - 1; Liquid	Liquid Gas	Small sample (50 mg) DSC	10

Thermodynamics Research Center / ThermoML | Thermochimica Acta

Interpretation of the global heat of melting in eutectic binary systems

Corvis, Yohann, Espeau, Philippe

ABSTRACT