Interfacial Reaction-Directed Green Synthesis of CeO 2 -MnO 2 Catalysts for Imine Production through Oxidative Coupling of Alcohols and Amines.

Direct oxidative coupling of alcohols with amines over cheap but efficient catalysts is a promising choice for imine formation. In this study, porous CeO 2 -MnO 2 binary oxides were prepared via an interfacial reaction between Ce 2 (SO 4 ) 3 and KMnO 4 at room temperature without any additives. The as-prepared porous CeO 2 -MnO 2 catalyst has a higher fraction of Ce 3+ , Mn 3+ , and Mn 4+ and contains larger surface area and more oxygen vacancies. During the oxidative coupling reaction of alcohol with amine to imine, the as-obtained CeO 2 -MnO 2 catalyst is motivated by the above encouraging characteristics and exhibits superior catalytic activity (98% conversion and 97% selectivity) and can also work effectively under a wide scope of temperatures and substrates. The in-depth in situ DRIFTS and density functional theory (DFT) results demonstrate that there is a strong interaction between CeO 2 and MnO 2 in the CeO 2 -MnO 2 catalyst, exhibiting especially a positive synergistic effect in the direct coupling of alcohol and amine reaction.