Abstract:
This paper objective was searching of oxidation process for some phenolic compounds (2-aminophenol, 2-chlorophenol, resorcinol) with chlorine dioxide, by use of molar ratio method. The analysis of oxidation process in water solutions, allowed identification of benzoquinone formation using ultraviolet and visible spectrophotometry, due to its specific maxima at 247 and 500 nm. Benzoquinone oxidation by chlorine dioxide is a slowly process during 12- 24 hours, when the solutions become colourless, and pH is
reduced with 2-3 units. The rate constants according to second order reaction, showed the following evolution of oxidation: a).a fast step, during 2-5 minutes, with k2 = 0.145⋅103 mol-1 s-1, for resorcinol; b).an intermediate step, in the next 30 minutes, when the reaction rate decreases about 50
times, k2 = 0.27⋅10 mol-1 s-1; c). a third step, a slow one, when benzoquinone is advanced oxidized. Phenolic compounds reactivity in
the oxidation process with chlorine dioxide according to the rate constants values was: resorcinol > 2-aminophenol ≅ 2-chlorophenol.
Keywords:
chlorine dioxide, phenolic compounds, advanced oxidation
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