Thermochemical properties of uracil and thymine have been evaluated using additional experiments. Standard (p0 = 0.1 MPa) molar enthalpies of formation in the gas phase at T = 298.15 K for uracil (298.1 +- 0.6) and for thymine (337.6 +- 0.9) kJ mol 1 have been derived from energies of combustion measured by static bomb combustion calorimetry and molar enthalpies of sublimation determined using the transpiration method. The G3 and G4 quantum-chemical methods were used for calculations of theoretical gaseous enthalpies of formation being in very good agreement with the re-measured experimental values.
Compounds
#
Formula
Name
1
CO2
carbon dioxide
2
N2
nitrogen
3
H2O
water
4
O2
oxygen
5
C4H4N2O2
2,4(1H,3H)-pyrimidinedione
6
C5H6N2O2
thymine
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
5
Vapor or sublimation pressure, kPa ; Crystal
Temperature, K; Crystal
Crystal
Gas
Transpiration method
9
POMD
6
Vapor or sublimation pressure, kPa ; Crystal
Temperature, K; Crystal
Crystal
Gas
Transpiration method
11
RXND
5
1
2
3
4
Specific internal energy of reaction at constant volume, J/g
Static bomb calorimetry
1
RXND
6
1
2
3
4
Specific internal energy of reaction at constant volume, J/g