Miranda, Margarida S.; Matos, Maria Agostinha R.; Morais, Victor M. F. published the artcile< Structure and energetics correlations in some chlorohydroxypyridines>, COA of Formula: C5H4ClNO, the main research area is chlorohydroxypyridine structure energetics correlation.
We have performed a study of the structure and energetics of some chlorohydroxypyridines based on exptl. calorimetry techniques and high level ab initio computational calculations The standard (p° = 0.1 MPa) molar enthalpies of formation of 2-chloro-3-hydroxypyridine (2-Cl-3-OHPy), 2-chloro-6-hydroxypyridine (2-Cl-6-OHPy) and 3-chloro-5-hydroxypyridine (3-Cl-5-OHPy) in the crystalline phase, at T = 298.15 K, were derived from the resp. standard massic energies of combustion measured by rotating-bomb combustion calorimetry, in oxygen, at T = 298.15 K. The standard molar enthalpies of sublimation, at T = 298.15 K, were measured by Calvet microcalorimetry. From these exptl. determined enthalpic parameters we have derived the standard molar enthalpies of formation of the three compounds in the gaseous phase, at T = 298.15 K: 2-Cl-3-OHPy, -(76.8 ± 2.0) kJ · mol-1; 2-Cl-6-OHPy, -(105.0 ± 1.7) kJ · mol-1, 3-Cl-5-OHPy -(61.2 ± 2.4) kJ · mol-1. These values were compared with estimates obtained from very accurate computational calculations using the G3(MP2)//B3LYP composite method and appropriately chosen reactions. These calculations have also been extended to the remaining chlorohydroxypyridine isomers that were not studied exptl. Based on B3LYP/6-31G* optimized geometries and calculated G3(MP2)//B3LYP absolute enthalpies some structure-energy correlations were discussed.
Journal of Chemical Thermodynamics published new progress about Formation enthalpy (molar). 96630-88-5 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, COA of Formula: C5H4ClNO.