Date of Award


Document Type

Honors Thesis (Open Access)


Colby College. Chemistry Dept.


D. Whitney King

Second Advisor

Thomas Shattuck


The radical dioxygen anion, superoxide has been shown to react with carbon dioxide in nonprotic and aqueous systems. Indirect evidence suggests that superoxide also reacts with carbon dioxide and carbonate species dissolved in water. This study involved conducting experiments to determine the decay rate of superoxide in the presence of carbon dioxide and carbonate species. Experiments were conducted by sparging an alkaline bicarbonate buffer with carbon dioxide and measuring the decay rate of superoxide added to the solution. Although the specific reaction mechanism and rates have not been determined first order superoxide decay rates as high as 3.8x10-2s-1 were obtained and an increasing trend in the rates was found with the increase of carbonic acid. Contamination from impurities and the inability to make a control solution made the exact determination and quantification of rates and mechanisms impossible at this time. This study laid the groundwork needed for the development of a robust mechanistic model for the decay of superoxide by reaction with carbon dioxide.


dioxygen anion, carbon dioxide, carbonate species, reaction in water, decay rate

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