The standard (p = 0.1 MPa) molar energy of combustion in oxygen, at T = 298.15 K, of 7-hydroxycoumarin was measured by static bomb calorimetry. The value of the standard molar enthalpy of sublimation was obtained by Calvet microcalorimetry and corrected to T = 298.15 K. Combining these results, the standard molar enthalpy of formation of the compound, in the gas phase, at T = 298.15 K, has been calculated, (337.5 +- 2.3) kJ mol-1. The values for the temperature of fusion, Tfusion, and for the fusion enthalpy, at T = Tfusion, are also reported. Additionally, high-level density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional with extended basis sets, the MC3BB and MC3MPW methods and more accurate correlated computational techniques of the MCCM suite have been performed for the compound. The agreement between experiment and theory gives confidence to estimate the enthalpy of formation of the remaining hydroxycoumarins substituted in the benzene ring.
Compounds
#
Formula
Name
1
CO2
carbon dioxide
2
H2O
water
3
O2
oxygen
4
C9H6O3
7-hydroxy-2H-chromen-2-one
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
4
Molar enthalpy of transition or fusion, kJ/mol ; Crystal
Crystal
Liquid
Air at 1 atmosphere
DSC
1
POMD
4
Triple point temperature, K ; Crystal
Crystal
Liquid
Air at 1 atmosphere
DTA
1
POMD
4
Molar enthalpy of vaporization or sublimation, kJ/mol ; Crystal