The subject invention provides a potentially economically viable method for the preparation of reactive superoxide ion in deep eutectic solvents (DES). The superoxide ion can be used for many applications, e.g. the degradation of hazardous chemicals at ambient conditions or in the synthesis of some special chemicals, e.g. carboxylic acids, aldehydes, and ketones from the corresponding alcohols. The superoxide ion can be formed by either the electrochemical reduction of oxygen in DES or by dissolving Group 1 (alkali metals) or Group 2 (alkaline earth metals) superoxides, e.g. potassium superoxide, in DES, with/without chemicals used for the enhancement of the solubility of the metal superoxide in the DES, e.g. crown ethers.