ABSTRACT

The description of the reassembling and testing of a twin heat conduction, high-precision, drop microcalorimeter for the measurement of heat capacities of small samples are presented. The apparatus, originally developed and used at the Thermochemistry Laboratory, Lund, Sweden, has now been reassembled and modernized, with changes being made as regarding temperature sensors, electronics and data acquisition system. The apparatus was thereafter thoroughly tested, using benzoic acid and hexafluorobenzene as test substances. The accuracy of the C_p;m (298.15 K) data obtained with this apparatus is comparable to that achieved by high-precision adiabatic calorimetry. Here we also present the results of heat capacity measurements on of some polyphenyls (1,2,3-triphenylbenzene, 1,3,5-triphenylbenzene, p-terphenyl, mterphenyl, o-terphenyl, p-quaterphenyl) at T = 298.15 K, measured with the renewed high precision heat capacity drop calorimeter system. The high resolution and accuracy of the obtained heat capacity data enabled differentiation among the ortho-, meta-, and para-phenyl isomers.

Compounds

#	Formula	Name
1	C7H6O2	benzoic acid
2	C6F6	hexafluorobenzene
3	C24H18	1,2,3-triphenylbenzene
4	C18H14	o-terphenyl
5	C18H14	m-terphenyl
6	C18H14	p-terphenyl
7	C24H18	1,1':4',1'':4'',1'''-quaterphenyl
8	C24H18	1,3,5-triphenylbenzene

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	1	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	Drop calorimetry	1
POMD	2	Molar heat capacity at constant pressure, J/K/mol ; Liquid	Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Drop calorimetry	1
POMD	3	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	Drop calorimetry	1
POMD	4	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	Drop calorimetry	1
POMD	5	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	Drop calorimetry	1
POMD	6	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	Drop calorimetry	1
POMD	7	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	Drop calorimetry	1
POMD	8	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	Drop calorimetry	1

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Reassembling and testing of a high-precision heat capacity drop calorimeter. Heat capacity of some polyphenyls at T = 298.15 K

Santos, L. M. N. B. F.[Luis M. N. B. F.], Rocha, M. A. A.[Marisa A.A.], Rodrigues, A. S. M. C.[Ana Sofia M.C.], Stejfa, V.[Vojtech], Fulem, M.[Michal], Bastos, M.[Margarida]

ABSTRACT