As-prepared and intercalated layered double hydroxides of the hydrocalumite type as efficient catalysts in various reactions

Abstract

The activities of the research group in the synthesis, characterization and, especially catalytic applications of layered double hydroxides (LDHs) of the hydrocalumite type are reviewed placing the work in literature context. In the project, CaFe- and CaAl-LDHs and their intercalated varieties were synthesized with wet chemical, mechanochemical and ultrasonically-assisted mechanochemical methods, and their structural characterization was performed with state-of-the-art methods. Metal ion [Mn(II), Cu(II), Fe(III) or Ni(II)]-amino acid (l-tyrosine, l-histidine or l-cysteine)−CaAl-LDH composites were also prepared and characterized. The as-prepared LDHs and composites were applied in a wide range of reactions like epoxidation/oxidation of olefins with or without additional functionality, the Baeyer-Villiger oxidation, cross-aldol dimerization–condensation or the Ullmann-type coupling reactions. The activities, selectivities and recycling abilities of the catalysts were investigated.