Electrosynthesis of H2O2 from O2 in gas diffusion electrodes for the preparation of organic peracids and the complex of H2O2 with urea

Abstract

Electrosynthesis of hydrogen peroxide from oxygen was performed in a gas-diffusion carbon black electrode in aqueous solutions of various salts with alkali metal and ammonium cations with urea additions and without them at current densities of 0.1–0.15 A cm−2. The resulting solutions containing 0.8–3.0 M H2O2 were concentrated to 25 M and dried with addition of urea to obtain the urea-H2O2 complex. The concentrated solutions of H2O2 were used to prepare peracetic and performic acids. Solid precipitates with up to 92 wt % urea perhydrate and up to 4 M peracid solutions were obtained. The presence of inorganic salts did not hinder the formation of these compounds. The presence of 1 M urea in solution had no adverse effect on the electrosynthesis of H2O2. These results indicate that the applications of electrosynthesis of H2O2 from O2 in carbon black gas-diffusion electrodes can be significantly expanded for further use of the resulting solutions for the synthesis of various products.