Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Heat capacity and thermodynamics of solid and liquid pyridine-3-carboxylic acid (nicotinic acid) over the temperature range 296 K to 531 K

Abhinav, J.[Joseph], Bernardes, C. E. S.[Carlos E. S.], Minas da Piedade, M. E.[Manual E.]
J. Chem. Thermodyn. 2012, 55, 23-28
ABSTRACT
The molar heat capacity of pyridine-3-carboxylic acid (nicotinic acid) for T = (296 to 531) K was investigated by differential scanning calorimetry (DSC) and Calvet-drop microcalorimetry. The measurements extended up to the liquid range and also covered the interval where a reversible and fast solid-solid (cr II to cr I) phase transition occurs. The molar enthalpies and entropies of that phase transition and of fusion were obtained as T_trs = (455.0 +- 0.2) K, Delta-H_trs = (0.90 +- 0.10) kJ mol-1, Delta-S_trs = (1.98 +- 0.22) J K-1 mol-1, T_fus = (509.91 +- 0.04) K, Delta-H_fus = (28.2 +- 0.1) kJ mol-1, and Delts-S_fus = (55.30 +- 0.16) J K-1 mol-1. By combining these experimental results with the previously reported Delta-H_sub (NA, cr II) at T = 366.5 K, the corresponding entropy in the gaseous state calculated at the B3LYP/6-31+G(d,p) level of theory, and Delta-H_f (NA, cr II) at T = 298.15 K, it was possible to estimate the standard molar Gibbs energy of formation functions necessary for the construction of the Delta-G_f vs. T diagram illustrating the enantiotropic nature of this system.
Compounds
# Formula Name
1 C6H5NO2 3-carboxylpyridine
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
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 1
  • Crystal 1
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 1
  • Triple point temperature, K ; Crystal 1
  • Crystal 1
  • Liquid
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 1
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 1
  • 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
  • 38
  • POMD
  • 1
  • 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
  • 27
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Small sample (50 mg) DSC
  • 8
  • POMD
  • 1
  • Molar enthalpy, kJ/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • Drop calorimetry
  • 1
  • POMD
  • 1
  • Molar enthalpy, kJ/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • Small sample (50 mg) DSC
  • 1