Modelling the photo-oxidation of hydrocarbons in sea water. Effect of salinity
María I. Gutiérrez, Marta Luiz, Norman A. García

The modelling of photoreactions of hydrocarbons in the marine environment was attempted. The salt effect (NaCl or LiCl between 0 and 0.45 M) on the singlet molecular oxygen-mediated photo-oxidation rate of two substrates of known reactivity was studied. The substrates used were sulfur- containing methionine (in water) and polynuclear hydrocarbon rubrene (acetonitrile-ethanol). Surprisingly the photo-oxidation rates, in solutions containing increasing amounts of salt, remained practically constant in spite of the decrease in the concentration of dissolved oxygen due to the presence of the salt. In the case of methionine these results were attributed to a compensation between the mentioned decrease in oxygen solubility and an increase in the photo-oxidation rate due to the effect of solvent polarity. In the case of rubrene, in the organic medium, the decrease in oxygen concentration was not large enough to affect the photooxidative pathway.

Keywords: Methionine, photo-oxidation, rubrene, salinity, sea water, singlet molecular oxygen.
Contents of this volume Sci. Mar. 58(3) : 207-211 Back PDF
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