Oxidation is the core technology to convert petrochemical based materials to commodity chemicals of higher oxidation state. However, oxidation reactions present some of the greatest challenges to the environment. Many of the industrial oxidation processes involved heavy metals or corrosive reagents, and are high in energy consumption.

We have demonstrated that 70% aqueous TBHP (tert-butyl hydroperoxide) with microwave irradiation is a green oxidation protocol for alkyl substituted aromatics. Methyl aromatics (toluenes and xylenes) can be oxidized directly to the industrially important carboxylic and dicarboxylic acids. Addition of tiny amount of ionic liquid and simultaneous cooling improves the efficiency of these oxidations. For other alkyl substituted aromatics, ketones are obtained in good yields. The reaction medium is water. No organic solvents, metal based reagents or catalysts are needed.

The oxidation of xylene isomers to the corresponding phthalic acids open up a green alternative to the synthesis of these economically important fine chemicals. In the case of p-xylene, the oxidized terephthalic acids precipitated out from the reaction mixtures.