ABSTRACT

The standard (p = 0.1 MPa) molar enthalpies of formation in the crystalline phases of ortho, meta and para-terphenyl isomers, at T = 298.15 K, were derived from the standard molar energies of combustion, measured by mini-bomb combustion calorimetry. The Knudsen mass-loss effusion technique was used to measure the dependence of the vapour pressure of the crystals with the temperature, thus deriving their standard molar enthalpies of sublimation by means of the Clausius Clapeyron equation. Combining the standard molar enthalpies of formation and sublimation of the crystalline terphenyls, the standard molar enthalpies of formation in the gaseous state, at T = 298.15 K, were derived for the three isomers.

Compounds

#	Formula	Name
1	CO2	carbon dioxide
2	H2O	water
3	O2	oxygen
4	C18H14	o-terphenyl
5	C18H14	m-terphenyl
6	C18H14	p-terphenyl

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	Phase	Method	#Points
POMD	4	Mass density, kg/m3 ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	measurement of volume and mass of pellet	1
POMD	4	Vapor or sublimation pressure, kPa ; Crystal	Temperature, K; Crystal	Crystal Gas	Calculated from knudsen effusion weight loss	35
POMD	5	Mass density, kg/m3 ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	measurement of volume and mass of pellet	1
POMD	5	Vapor or sublimation pressure, kPa ; Crystal	Temperature, K; Crystal	Crystal Gas	Calculated from knudsen effusion weight loss	34
POMD	6	Mass density, kg/m3 ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	measurement of volume and mass of pellet	1
POMD	6	Vapor or sublimation pressure, kPa ; Crystal	Temperature, K; Crystal	Crystal Gas	Calculated from knudsen effusion weight loss	35
RXND	4 1 2 3	Specific internal energy of reaction at constant volume, J/g			Micro-bomb calorimetry	1
RXND	5 1 2 3	Specific internal energy of reaction at constant volume, J/g			Micro-bomb calorimetry	1
RXND	6 1 2 3	Specific internal energy of reaction at constant volume, J/g			Micro-bomb calorimetry	1

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Standard molar enthalpies of formation and of sublimation of the terphenyl isomers

Ribeiro da Silva, M. A. V.[Manuel A. V.], Santos, L. M. N. B. F.[Luis M. N. B. F.], Lima, L. M. S. S. M. S. S.[Luis M. Spencer S.]

ABSTRACT