Cu and Fe Catalysts Based on Porous Aromatic Frameworks for Oxidation of Alkylaromatics

In this paper, we present a new simple approach to synthesizing catalysts for the oxidation of alkylaromatics based on the immobilization of metal ions by conventional ion exchange. By sulfation of high-stable porous polymers, porous aromatic framework (PAFs), we prepared the PAF-30-SO3H carrier, which was used for immobilization of Cu(II) and Fe(III) ions. The resulting Cu/PAF-30-SO3H and Fe/PAF-30-SO3H catalysts were successfully applied for the oxidation of ethylbenzene, 3-ethyltoluene, n-propylbenzene, Indane, and tetralin to the corresponding α-ketones. The catalysts were stable against metal leaching and showed high activity in alkylaromatics oxidation: The conversion of substrates reached 80% in 24 h at 80 °C, and did not decrease during for at least 5 cycles. The performance of catalysts was also compared with Cu/PAF-30-MEA and Fe/PAF-30-MEA catalysts, synthesized from PAF-30-MEA carrier, which structure was modified with monoethanolamine-based chelating groups. The structure of the materials and catalysts was established using advanced analytical techniques: low temperature N2 adsorption, elemental analysis, FTIR spectroscopy, solid state NMR, XPS, TEM, and EDX mapping.