Catalytic Performance Of Metal Oxide Nanomaterials On Epoxidation And Oxidative Carboxylation Reaction Of Alkenes

Metal oxide nanomaterials have become a hotspot of organic reaction catalysis because of their large specific surface area,small size,large number of active sites,good stability and recycling.In this paper,small size metal oxide nanoparticles were prepared by hydrothermal method and used to catalyze the oxidation carboxylation of olefin.Moreover,catalytic performance and stability of metal oxide nanomaterials were investigated.The main research contents were as follows:1.The effect of Nano-Al₂O₃ as the catalystn the epoxidation of olefin was studied in the presence of molecular oxygen and 3,5,5-trimethylhexanal.It was found that the catalytic activity of Nano-Al₂O₃was in the reaction affected by temperature,solvent and various aldehydes.When the reaction was carried out in the presence of Nano-Al₂O₃ as the catalyst and3,5,5-trimethylhexanal as the co-reductant under 1 atm of molecular oxygen at 60°C in Me CN for 24 h,the epoxide product was obtained in 90%yield.Various kinds of alkenes could undergo the oxidation to give rise to the corresponding epoxides in the optimal reaction conditions with moderate to excellent yields and>99%selectivity,which indicate the reaction system has good applicability of reactive substrates.It was found that no obvious loss of activity and the no significant changes of morphology and structure characterized by SEM and XRD have been found in comparison with the Nano-Al₂O₃before being used were observed,indicating the good recyclability and stability of the nanocatalyst.2.Nano-Fe₂O₃ with high yield,regular morphology and uniform size was prepared by hydrothermal method,and the application of three-component catalytic system of Nano-Fe₂O₃/TBHP-TBAB in the reaction of styrene and carbon dioxide was investigated.It was found that the oxidative carboxylation of styrene was catalyzed by Nano-Fe₂O₃/TBHP-TBAB catalytic system under relatively mild reaction conditions and obtain a medium yield.Morover,the catalytic system has good catalytic effect on other substituted styrene derivatives.It was found that no obvious loss of activity and the no significant changes of morphology and structure characterized by SEM and XRD have been found in comparison with the Nano-Fe₂O₃before being used were observed,indicating the good recyclability and stability of the nanocatalyst.