ABSTRACT

The dilution enthalpies of nicotinamide (NA) and isonicotinamide (INA) in (dimethyl sulfoxide (DMSO) + water) and (dimethylformamide (DMF) + water) mixed solvents (M1 and M2) at 298.15 K have been determined, respectively, using an isothermal titration calorimeter (MicroCal ITC200). On the basis of the McMillan-Mayer theory, enthalpic pairwise self-interaction coefficients (hxx) of NA and INA in both M1 and M2 aqueous mixed solvents (mole fractions of cosolvents xcos = 0 to 0.10) have been calculated. It was found that the values of hxx are all large negative, with the relative magnitudes hxx(NA) less than hxx(INA) less than 0 in both M1 and M2, and hxx (in M1) greater than hxx (in M2) for both NA and INA, and that all of them increase monotonously with the concentrations of cosolvents (both DMF and DMSO). It implies that an intense exothermic effect accompanies with the pairwise hydrophilic hydrophilic self-interactions, in which the meso-isomer (NA) behaves as a stronger molecular associator than the para-isomer (INA).

Compounds

#	Formula	Name
1	C6H6N2O	3-pyridinecarboxamide
2	C6H6N2O	4-pyridinecarboxamide
3	C2H6OS	dimethyl sulfoxide
4	C3H7NO	dimethylformamide
5	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	3 1 5	Molar enthalpy of dilution, kJ/mol ; Liquid	Solvent: Mole fraction - 3; Liquid Initial molality of solute, mol/kg; Liquid Final molality of solute, mol/kg; Liquid	Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Calvet calorimetry	126
POMD	3 2 5	Molar enthalpy of dilution, kJ/mol ; Liquid	Solvent: Mole fraction - 3; Liquid Initial molality of solute, mol/kg; Liquid Final molality of solute, mol/kg; Liquid	Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Calvet calorimetry	108
POMD	4 1 5	Molar enthalpy of dilution, kJ/mol ; Liquid	Solvent: Mole fraction - 4; Liquid Initial molality of solute, mol/kg; Liquid Final molality of solute, mol/kg; Liquid	Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Calvet calorimetry	108
POMD	4 2 5	Molar enthalpy of dilution, kJ/mol ; Liquid	Solvent: Mole fraction - 4; Liquid Initial molality of solute, mol/kg; Liquid Final molality of solute, mol/kg; Liquid	Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Calvet calorimetry	108
POMD	1 5	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	Calvet calorimetry	18

Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

Dilution Enthalpies and Enthalpic Pairwise Self-Interactions of Nicotinamide and Isonicotinamide in (Dimethylformamide + Water) and (Dimethylsulfoxide + Water) Mixed Solvents at 298.15 K

Chen, N.[Nan], Jia, Z.-P.[Zhao-Peng], Wang, H.-Q.[Hua-Qin], Zhu, L.-Y.[Li-Yuan], Hu, X.-G.[Xin-Gen]

ABSTRACT