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.
Luiz
Marta
M
Departamento de Química, Facultad de Ciencias Naturales, Universidad Nacional de la Patagonia-SJB, Comodoro Rivadavia, Argentina.
Biasutti
M Alicia
MA
García
Norman A
NA
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