Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Thermochemistry of aqueous pyridine-3-carboxylic acid (nicotinic acid)

Goncalves, E. M.[Elsa M.], Rego, T. S.[Talita S.], Minas da Piedade, M. E.[Manual E.]
J. Chem. Thermodyn. 2011, 43, 6, 974-979
ABSTRACT
The molar enthalpy of solution of solid nicotinic acid (NA) at T = 298.15 K, to give an aqueous solution of molality m = 3.748 x 10-3 mol kg-1, was determined as (19,927 +- 48) J mol-1, by solution calorimetry. Enthalpies of dilution, of 0.1005 mol kg-1 aqueous nicotinic acid to yield final solutions with molality in the approximate range (0.03 to 0.09) mol kg-1 were also measured by flow calorimetry. Combining the two sets of data and the results of pH measurements, with values of proton dissociation enthalpies and enthalpy of formation for NA(cr) selected from the literature, it was possible to derive the standard molar enthalpies of formation of the three nicotinic acid species involved in protonation/deprotonation equilibria, at infinite dilution. Finally, the enthalpy of solution of nicotinic acid at T = 298.15 K, under saturation conditions (m = 0.138 mol kg-1), and the standard molar enthalpy of formation of the corresponding solution could also be obtained as (19,448 +- 48) J mol-1 and (324.9 +- 1.2) kJ mol-1, respectively.
Compounds
# Formula Name
1 C6H5NO2 3-carboxylpyridine
2 H2O water
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
  • 1
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 1
  • Normal melting temperature, K ; Crystal 1
  • Crystal 1
  • Liquid
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 1
  • Crystal 1
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 1
  • 2
  • Molar enthalpy of solution, kJ/mol ; Liquid
  • Molality, mol/kg - 1; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • ISOPERIBOL
  • 5
  • POMD
  • 1
  • 2
  • Molar enthalpy of dilution, kJ/mol ; Liquid
  • Final molality of solute, mol/kg; Liquid
  • Initial molality of solute, mol/kg; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Flow calorimetry
  • 16