Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Thermochemical study of chloropyrazines and chloroquinoxalines

Morais, V. M. F.[Victor M. F.], Miranda, M. S.[Margarida S.], Matos, M. A. R.[M. Agostinha R.]
J. Chem. Thermodyn. 2004, 36, 5, 377-383
ABSTRACT
The standard (po=0.1 MPa) molar enthalpies of formation for liquid 2-chloropyrazine and crystalline 2,6-dichloropyrazine, 2,3-dichloroquinoxaline and 2,3,6,7-tetrachloroquinoxaline were derived from the standard molar enthalpies of combustion, in oxygen, to yield CO2(g), N2(g), and HCl ? 600H2O(l), at the temperature T=298.15 K, measured by rotating-bomb combustion calorimetry. The standard molar enthalpies of vaporization or of sublimation, at T=298.15 K, were measured by Calvet microcalorimetry. Density functional theory with the B3LYP functional and two different basis sets, 6-31G* and 6-311G**, was used to optimize the geometries of all chloro-substituted pyrazines and some chloro-substituted quinoxalines. The calculation of the energy of isodesmic reactions allowed the estimation of the standard molar enthalpies of formation in the gas phase for all compounds including some not studied experimentally.
Compounds
# Formula Name
1 ClH hydrogen chloride
2 CO2 carbon dioxide
3 N2 nitrogen
4 H2O water
5 O2 oxygen
6 C4H3ClN2 chloropyrazine
7 C4H2Cl2N2 2,6-dichloropyrazine
8 C8H4Cl2N2 2,3-dichloroquinoxaline
9 C8H2Cl4N2 2,3,6,7-tetrachloroquinoxaline
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
  • 6
  • Molar enthalpy, kJ/mol ; Gas
  • Temperature, K; Gas
  • Pressure, kPa; Gas
  • Gas
  • OTHER
  • 1
  • POMD
  • 7
  • Molar enthalpy, kJ/mol ; Gas
  • Temperature, K; Gas
  • Pressure, kPa; Gas
  • Gas
  • OTHER
  • 1
  • POMD
  • 8
  • Molar enthalpy, kJ/mol ; Gas
  • Temperature, K; Gas
  • Pressure, kPa; Gas
  • Gas
  • OTHER
  • 1
  • POMD
  • 9
  • Molar enthalpy, kJ/mol ; Gas
  • Temperature, K; Gas
  • Pressure, kPa; Gas
  • Gas
  • OTHER
  • 1
  • RXND
  • 1
  • 6
  • 2
  • 3
  • 4
  • 5
  • Specific internal energy of reaction at constant volume, J/g
  • BOMBRT:Method:BOMBRT
  • 1
  • RXND
  • 8
  • 1
  • 2
  • 3
  • 4
  • 5
  • Specific internal energy of reaction at constant volume, J/g
  • BOMBRT:Method:BOMBRT
  • 1
  • RXND
  • 1
  • 9
  • 2
  • 3
  • 4
  • 5
  • Specific internal energy of reaction at constant volume, J/g
  • BOMBRT:Method:BOMBRT
  • 1
  • RXND
  • 7
  • 1
  • 2
  • 3
  • 5
  • Specific internal energy of reaction at constant volume, J/g
  • BOMBRT:Method:BOMBRT
  • 1