Surface characterization and catalytic evaluation of manganese nodule leached residue toward oxidation of benzene to phenol

Water washed manganese nodule leached residue (WMNLR) calcined at different temperatures was characterized by XRD, FTIR, TG-DTA, surface area, surface oxygen, and surface acid sites. Surface area, surface oxygen, surface hydroxyl group, and surface acid sites increase up to 400 °C and then decrease with further rise in calcination temperature up to 700 °C. The catalytic activity of the calcined samples was tested for single-step oxidation of benzene to phenol using hydrogen peroxide as the oxidant and acetic acid as the solvent at room temperature. The influence of various reaction parameters such as solvent, concentration of solvent, oxidant amount, time, temperature, and catalyst amount was studied to optimize the reaction conditions. WMNLR calcined at 400 °C showed the highest catalytic activity towards oxidation of benzene with 12.7% conversion and 98% selectivity.

Manganese nodule leached residue is an efficient catalyst for single-step benzene oxidation to phenol. H2O2 reacts with WMNLR to give hydroxyl radical through a redox mechanism, which attacks the benzene ring to give phenol. Among calcined samples WMNLR-400 shows the highest catalytic activity toward oxidation of benzene with 12.7% conversion and 98% selectivity.Figure optionsDownload as PowerPoint slide