ABSTRACT

The heat capacities of 6-chlorouracil and 5-chlorouracil isomers were measured using a Quantum Design physical properties measurement system (PPMS) based on a heat pulse relaxation method over the temperature range from (1.9 to 300) K, and the experimental data were fitted as a function of temperature using a series of theoretical and empirical models for the appropriate temperature ranges. The results of these fits were used to calculate thermodynamic function values, C0p,m, T0Som, and deltaT0Hom from T = (0.5 to 300) K. The standard molar heat capacities, entropies and enthalpies of 6-chlorouracil and 5-chlorouracil at 298.15 K and 0.1 MPa were determined to be Cop,m= (136.94 +- 1.37) J K-1mol-1 and (137.95 +- 1.38) J K-1mol-1, Som= (156.87 +- 1.57) J K-1mol-1and (154.97 +- 1.55) J K-1mol-1 and Hom= (23.01 +- 0.23) kJ mol-1and (23.07 +- 0.23) kJ mol-1, respectively.

Compounds

#	Formula	Name
1	C4H3ClN2O2	6-chlorouracil
2	C4H3ClN2O2	5-chloro-2,4-pyrimidinedione

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	RELAXCAL	59
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	RELAXCAL	46
POMD	1	Molar entropy, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	RELAXCAL	46
POMD	1	Molar enthalpy, kJ/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	RELAXCAL	46
POMD	2	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	RELAXCAL	59
POMD	2	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	RELAXCAL	46
POMD	2	Molar entropy, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	RELAXCAL	46
POMD	2	Molar enthalpy, kJ/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	RELAXCAL	46

Thermodynamics Research Center / ThermoML | Thermochimica Acta

Calorimetric studies on two halogenated uracil isomers

Zou, G.[Guanglong], Cheng, Z.[Ze], Zhang, S.[Shihui], Tan, Z.[Zhicheng], Zhang, J.[Jian], Shi, Q.[Quan]

ABSTRACT