Abstract (EN):
The standard (pdegrees = 0.1MPa) molar enthalpies of formation for 2-, 3- and 4-cyanophenol in the gaseous phase were derived from the standard molar enthalpies of combustion in oxygen at T D 298: 15 K, measured by static bomb combustion calorimetry, and the standard molar enthalpies of sublimation at 298.15 K, measured by Calvet microcalorimetry: 2-cyanophenol, (32.8 +/- 2.1) kJ-mol(-1); 3-cyanophenol, (37.8 +/- 2.2) kJ-mol(-1); 4-cyanophenol, (35.1 +/- 2.5)-kJ-mol(-1). Ab initio geometry optimizations of the three cyanophenols and respective phenoxyl radicals and phenoxide anions were performed using the 6-31G* basis sets. Single-point MP2 and DFT energy calculations allowed the estimation of the enthalpies of formation in the gaseous phase, the O-H bond dissociation energies, and the gas-phase acidities of the three cyanophenols. The theoretical results are generally in good agreement with the experimental findings.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Contacto:
marmatos@fc.up.pt
Nº de páginas:
14