Thermodynamics Research Center / ThermoML | Thermochimica Acta

Temperature-dependent behavior of enthalpies and heat capacities of solution in water for thiourea and its N,N'-dimethylsubstituted derivative

Ivanov, E. V.[Evgeniy V.], Batov, D. V.[Dmitriy V.]
Thermochim. Acta 2013, 558, 10-15
ABSTRACT
Molar enthalpies of solution in water for thiourea (TU) and 1,3-dimethylthiourea (1,3-DMTU) were measured calorimetrically in the temperature range from (278.15 to 313.13) K at ambient pressure. Experimental results were used to derive limiting or standard (at infinite dilution) molar enthalpies of solution and hydration, changes in heat capacity due to the solution process and solute limiting molar heat capacities. Molar enthalpies for dilution of aqueous TU and 1,3-DMTU were also measured at T = 298.15 K. The enthalpic coefficients for pair-wise interactions between hydrated solute molecules were estimated using the McMillan-Mayer formalism. The latter quantity was found to be negative for both TU and 1,3-DMTU, decreasing in magnitude on going from the unsubstituted solute to its N,N'-methylated analog. Hydration behavior of both TU and 1,3-DMTU was discussed in comparison with that of urea and the corresponding dimethylsubstituted derivative.
Compounds
# Formula Name
1 CH4N2S thiourea
2 C3H8N2S N,N'-dimethylthiourea
3 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
  • 3
  • Molar enthalpy of solution, kJ/mol ; Liquid
  • Temperature, K; Liquid
  • Molality, mol/kg - 1; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • ISOPERIBOL
  • 9
  • POMD
  • 1
  • 3
  • Molar enthalpy of dilution, kJ/mol ; Liquid
  • Initial molality of solute, mol/kg; Liquid
  • Final molality of solute, mol/kg; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • ISOPERIBOL
  • 8
  • POMD
  • 2
  • 3
  • Molar enthalpy of solution, kJ/mol ; Liquid
  • Temperature, K; Liquid
  • Molality, mol/kg - 2; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • ISOPERIBOL
  • 6
  • POMD
  • 2
  • 3
  • Molar enthalpy of dilution, kJ/mol ; Liquid
  • Initial molality of solute, mol/kg; Liquid
  • Final molality of solute, mol/kg; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • ISOPERIBOL
  • 6