Thermochemical and theoretical studies of 2-hydroxyquinoxaline, 2,3-dihydroxyquinoxaline, and 2-hydroxy-3-methylquinoxaline

• Tipo: Artigo em Revista Científica Internacional
• Data: 2000

Autores

da Silva, MAVR (Autor) FCUP; Matos, MAR (Autor) FCUP; Rio, CMA (Autor) Outra; Miranda, MS (Autor) Outra; Morais, VMF (Autor) ICBAS

Revista

Título: Journal of Physical Chemistry A

Vol. 104

Páginas: 6644-6648

ISSN: 1089-5639

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 14 Citações

Scopus - 15 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-000-ZGB

DOI: 10.1021/jp000694y

Abstract (EN): The standard (p degrees = 0.1 MPa) molar enthalpies of formation for crystalline 2-hydroxyquinoxaline, 2,3-dihydroxyquinoxaline, and 2-hydroxy-3-methylquinoxaline were derived from the standard molar enthalpies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The standard molar enthalpies of sublimation, at T = 298.15 K, of the three compounds were measured by Calvet microcalorimetry. The derived standard molar enthalpies of formation in the gaseous phase are 45.9 +/- 4.3 kJ.mol(-1) for 2-hydroxyquinoxaline, -(179.2 +/- 5.3) kJ.mol(-1) for 2,3-dihydroxyquinoxaline, and -(8.8+/- 4.9) kJ.mol(-1) for 2-hydroxy-3-methylquinoxaline. In addition, theoretical calculations using the density functional theory and the B3LYP/6-311G** hybrid exchange-correlation energy functional were performed for these molecules in order to obtain the most stable geometries and to access their relative stability. The theoretical results are in general good agreement with experimental findings.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 5