Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Experimental thermochemical study of two 2-alkylbenzimidazole isomers (alkyl=propyl and isopropyl)

Ribeiro da Silva, M. A. V.[Manuel A. V.], Ribeiro da Silva, M. D. M. C.[Maria D. M. C.], Amaral, L. M. P. F.[Luisa M. P. F.], Jimenez, P.[Pilar], Roux, M. V.[MarIa Victoria], Davalos, J. Z.[Juan Z.], Temprado, M.[Manuel], Cabildo, Pilar, Claramunt, Rosa, Elguero, J.[Jose], Mo, O.[Otilia], Yanez, M.[Manuel]
J. Chem. Thermodyn. 2004, 36, 6, 533-539
ABSTRACT
This paper reports the values of the standard (po=0.1 MPa) molar enthalpy of formation in the condensed, at T=298.15 K, for 2-R-benzimidazoles (R=propyl, isopropyl), derived from, the respective enthalpies of combustion in oxygen, measured by static bomb combustion calorimetry and the standard molar enthalpies of sublimation, at T=298.15 K, obtained using Calvet microcalorimetry in the case of 2-isopropylbenzimidazole and, by the variation of vapour pressures, determined by the Knudsen effusion technique, with temperatures between (344 and 365) K for 2-propylbenzimidazole. Heat capacities, in the temperature ranges from T=268 K to near their respective melting temperatures, T=421 K for 2-propylbenzimidazole and T=464 K for 2-isopropylbenzimidazole, were measured with a differential scanning calorimeter. These values were used to derive the standard molar enthalpies of formation, of the two 2-benzimidazole derivatives, in gaseous phase.
Compounds
# Formula Name
1 CO2 carbon dioxide
2 N2 nitrogen
3 H2O water
4 O2 oxygen
5 C10H12N2 1H-benzimidazole, 2-propyl-
6 C10H12N2 1H-benzimidazole, 2-(1-methylethyl)-
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
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 5
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 5
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • Small sample (50 mg) DSC
  • 22
  • POMD
  • 5
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • Small sample (50 mg) DSC
  • 5
  • POMD
  • 5
  • Vapor or sublimation pressure, kPa ; Crystal
  • Temperature, K; Crystal
  • Crystal
  • Gas
  • Calculated from knudsen effusion weight loss
  • 5
  • POMD
  • 6
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 6
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 6
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • Small sample (50 mg) DSC
  • 26
  • POMD
  • 6
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • Small sample (50 mg) DSC
  • 9
  • POMD
  • 6
  • Molar enthalpy, kJ/mol ; Gas
  • Temperature, K; Gas
  • Pressure, kPa; Gas
  • Gas
  • Drop calorimetry
  • 1
  • RXND
  • 5
  • 1
  • 2
  • 3
  • 4
  • Specific internal energy of reaction at constant volume, J/g
  • BOMBMI:Method:BOMBMI
  • 1
  • RXND
  • 6
  • 1
  • 2
  • 3
  • 4
  • Specific internal energy of reaction at constant volume, J/g
  • BOMBST:Method:BOMBST
  • 1