Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 1 de 1
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Phys Chem Chem Phys ; 13(28): 12745-54, 2011 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-21670827

RESUMO

The phenol, α-tocopherol, can be electrochemically oxidised in a -2e(-)/-H(+) process to form a diamagnetic cation that is long-lived in dry organic solvents such as acetonitrile and dichloromethane, but in the presence of water quickly reacts to form a hemiketal. Variable scan rate cyclic voltammetry experiments in acetonitrile with carefully controlled amounts of water between 0.010 M-0.6 M were performed in order to determine the rate of reaction of the diamagnetic cation with water. The water content of the solvent was accurately determined by Karl Fischer coulometric titrations and the voltammetric data were modelled using digital simulation techniques. The oxidation peak potential of α-tocopherol measured during cyclic voltammetry experiments was found to shift to less positive potentials as increasing amounts of water (0.01-0.6 M) were added to the acetonitrile, which was interpreted based on hydrogen-bonding interactions between the phenolic hydrogen atom and water. Several other phenols were examined and they displayed similar voltammetric features to α-tocopherol, suggesting that interactions of phenols with trace amounts of water were a common occurrence in acetonitrile. The H-bonding interactions of α-tocopherol with water were also examined via NMR and UV-vis spectroscopies, with the voltammetric and spectroscopic studies extended to include other coordinating solvents (dimethyl sulfoxide and pyridine).


Assuntos
Acetonitrilas/química , Fenóis/química , Água/química , alfa-Tocoferol/química , Hidroxitolueno Butilado/análogos & derivados , Hidroxitolueno Butilado/química , Simulação por Computador , Cresóis/química , Dimetil Sulfóxido/química , Eletroquímica , Ligação de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética , Modelos Químicos , Estrutura Molecular , Oxirredução , Piridinas/química , Solventes/química , Espectrofotometria Ultravioleta , Água/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...