Towards Mechanistic Understanding of Liquid-Phase Cinnamyl Alcohol Oxidation with tert-Butyl Hydroperoxide over Noble-Metal-Free LaCo 1-x Fe x O 3 Perovskites

• Published in: ChemPlusChem (Weinheim, Germany) Vol. 84; no. 8; pp. 1155 - 1163
• Main Authors: Waffel, Daniel, Alkan, Baris, Fu, Qi, Chen, Yen-Ting, Schmidt, Stefan, Schulz, Christof, Wiggers, Hartmut, Muhler, Martin, Peng, Baoxiang
• Format: Journal Article
• Language: English
• Published: Germany 01-08-2019
• Subjects: oxidation; spray-flame synthesis; heterogeneous catalysis; reactive intermediates; perovskite phases
• ISSN: 2192-6506; 2192-6506
• DOI: 10.1002/cplu.201900429

Noble-metal-free perovskite oxides are promising and well-known catalysts for high-temperature gas-phase oxidation reactions, but their application in selective oxidation reactions in the liquid phase has rarely been studied. We report the liquid-phase oxidation of cinnamyl alcohol over spray-flame synthesized LaCo
Fe
O
perovskite nanoparticles with tert-butyl hydroperoxide (TBHP) as the oxidizing agent under mild reaction conditions. The catalysts were characterized by XRD, BET, EDS and elemental analysis. LaCo
Fe
O
showed the best catalytic properties indicating a synergistic effect between cobalt and iron. The catalysts were found to be stable against metal leaching as proven by hot filtration, and the observed slight deactivation is presumably due to segregation as determined by EDS. Kinetic studies revealed an apparent activation energy of 63.6 kJ mol
. Combining kinetic findings with TBHP decomposition as well as control experiments revealed a complex reaction network.