Thermochemical and theoretical study of tert-butyl and di-tert-butylphenol isomers

• Tipo: Artigo em Revista Científica Internacional
• Data: 1999

Autores

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

Revista

Título: Journal of Organic Chemistry

Vol. 64

Páginas: 8816-8820

ISSN: 0022-3263

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 26 Citações

Scopus - 27 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-001-2T6

DOI: 10.1021/jo990801o

Abstract (EN): The standard (p(o) = 0.1MPa) molar enthalpies of formation for 2-, 3-, and 4-tert-butylphenol and 2,4- and 2,6-di-tert-butylphenol in the gaseous phase were derived from the standard molar enthalpies of combustion, in oxygen, at 298.15 K, measured by static bomb combustion calorimetry and the standard molar enthalpies of evaporation at 298.15 K, measured by Calvet microcalorimetry: 2-tert-butylphenol, -184.7 +/- 2.6 kJ mol(-1); 3-tert-butylphenol, -198.0 +/- 2.1 kJ mol(-1); 4-tert-butylphenol, -187.3 +/- 3.3 kJ mol(-1); 2,4-di-tert-butylphenol -283.3 +/- 3.8 kJ mol(-1), 2,6-di-tert-butylphenol -272.0 +/- 4.0 kJ mol(-1). The most stable geometries of all mono- and disubstituted phenols as well as those of the corresponding radicals were obtained, respectively, by ab initio restricted Hartree-Fock (RHF) and restricted Hartree-Fock open shell (ROHF) methods with the 6-31G* basis set. The resulting geometries were then used to obtain estimates of the effect of the tert-butyl substituent on the O-H bond dissociation energy and on the formation enthalpies of all substituted phenols.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 5