Effect of reverse micelles on the Rose Bengal-sensitized photo-oxidation of 1- and 2-hydroxynaphthalenes.
Benzylhexadecyl dimethylammonium chloride (BHDC) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) water-in-oil micro-emulsions were employed to study the influence of medium heterogeneity on singlet molecular oxygen [O(2)((1)Delta(g))]-mediated degradation of 1-hydroxynaphthalene (1-OHN) and 2-hydroxynaphthalene (2-OHN) in their naphthoate form. The kinetic study in the micellar system, that was considered as a closer model for the environment of contaminants in natural polluted waters, consisted of a comparative work with the process in homogeneous solution, by varying surfactant structure and water content of the micro-emulsion. While it is known that 1-OHN and 2-OHN are rapidly and efficiently photo-oxidised in aqueous medium, time-resolved phosphorescence detection of O(2)((1)Delta(g)) and stationary photolysis experiments demonstrate that both the values for the overall and reactive rate constants for the quenching of O(2)((1)Delta(g)) and the photo-oxidation efficiencies are lowered in BHDC micelles, whereas the photo-oxidative process in AOT micro-emulsions was totally inhibited. Results are interpreted and discussed on the basis of different locations of the probe in the micellar environment.
Departamento de Química, Facultad de Ciencias Naturales, Universidad Nacional de la Patagonia-SJB, Comodoro Rivadavia, Argentina.
Marta
M
Luiz
M Alicia
MA
Biasutti
Norman A
NA
García
D007202:Indicators and Reagents; D007700:Kinetics; D008823:Micelles; D009284:Naphthols / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry; D012395:Rose Bengal
D007202:Indicators and Reagents; D008823:Micelles; D009284:Naphthols; D012395:Rose Bengal