Direct synthesis of H2O2 in methanol at low pressures over Pd/C catalyst: Semi-continuous process

The production of H2O2via direct synthesis has been studied in depth over the last decades, due to the possibilities given by the discovery of active catalysts based on nanotechnology and selective active metals. However, the process is also complicated because of the coexistence of three phases, where mass transfer between gas and liquid (solvent) limits the concentration of O2 and H2 in contact with the solid catalyst sites, and subsequently the final H2O2 productivity. High pressures are normally used to enhance mass transfer by increasing the solubility. In this work, we explore the influence of low pressures, in order to optimise the reaction reducing mechanical requirements. Pressures from 0.1 to 0.9 MPa in a semi-continuous reactor have been tested, obtaining H2O2 concentrations up to 1.33 wt.% and a selectivity from 44.9% to 69.0%. A nano-Pd/C commercial catalyst and methanol as solvent have been used.

.Figure optionsDownload high-quality image (151 K)Download as PowerPoint slideResearch highlights▶ The production of H2O2via direct synthesis is studied in a semi-continuous reactor. ▶ Nano-Pd/C commercial catalyst and methanol as solvent are used. ▶ Low pressures (below 0.9 MPa) and low temperatures (below 40 °C) are used. ▶ H2O2 concentrations up to 1.33 wt.% obtained. ▶ Yields up to ca. 40% and selectivities up to ca. 70% achieved.