We report a study on the energetics and structural properties of gallic (1) and ellagic (2) acids. The experimental values of standard enthalpy of formation in solid state at 298.15 K, deltafHm0 (cd) of 1 as (-985.0 +- 2.9 kJ*mol-1) and 2 as (-1377.9 +- 4.7 kJ*mol-1) have been determined. The vapour pressure of 1 have been measure by Knudsen effusion methodology and the derived enthalpy of sublimation, deltacdgHm0, was combined with the deltafHm0 (cd) in order to derive its gas-phase enthalpy of formation, deltafHm0(1,g) = -835.7 +- 4.0 kJ*mol-1. Quantum chemical calculations, at DFT (M05-2X) and composite ab initio Gn (n = 3, 4) levels of theory, provided the consistency of the experimental results and a plausible estimation of deltafHm0 (g) of 2 as (-1128.6 +- 6.4 kJ*mol-1), which was deduced from the isodesmic-reactions methodology.
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
Normal melting temperature, K ; Crystal
Crystal
Liquid
Air at 1 atmosphere
DTA
1
POMD
4
Molar heat capacity at constant pressure, J/K/mol ; Crystal
Temperature, K; Crystal
Pressure, kPa; Crystal
Crystal
DSC
209
POMD
4
Vapor or sublimation pressure, kPa ; Crystal
Temperature, K; Crystal
Crystal
Gas
Calculated from knudsen effusion weight loss
14
POMD
5
Molar heat capacity at constant pressure, J/K/mol ; Crystal
Temperature, K; Crystal
Pressure, kPa; Crystal
Crystal
DSC
263
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