Enhancing Base-metal Catalytic Efficiency By A Bio-inspired Hydrophobic Catalyst In Liquid-phase Selective Oxidation

The selective oxidation reactions, which convert bulk chemicals intohigher-value products, are core technologies in organic synthesis andindustrial applications. Among the various catalysts, ruthenium has beenwidely employed because of its unique electronic structure. Although manybase metal such as Mn, Fe, Cu have been applied in industry, they do notreach the catalytic activity of Ru. Recently, searching for base metal catalystsas substitution for ruthenium in selective oxidation attracts much attention.Inspired by nature phospholipids bilayer, here we report a catalyst with elasticbi-dimensional hydrophobic region by using brucite-like layers of layereddouble hydroxides （LDHs） modified by hydrophobic organic cations. Themain results in our work are listed as follows:（1） Due to the unique intercalation properties of LDHs, SAS surfactant ascharge-balancing anions anchoring to the layers can both increase theinterlayer spacing and endow hydrophobic property to the interlayer gallery ofLDHs. Mn（tpp）OAc between the hydrophobic layers to mimic thephospholipids bilayer, Mn（tpp）OAc on the hydrophobic layers, Mn（tpp）OAcgathered around hydrophobic layers surface and Mn（tpp）OAc on the hydrophilic layers were built.（2） Bio-inspired hydrophobic catalyst catalytic epoxidation reaction andget the conversion rate of41%after6h, much higher than the homogeneousphase of Mn（tpp）OAc and other design contrast catalyst so far as to reach thecatalytic activity of ruthenium.TOF reached4108h^-1, much higher than thecatalytic performance in other literature.（3） Catalyzing epoxidation reaction over substrates with different LogP_o/wis to study the relaevancy of the hydrophobic catalyst and hydrophobicenviroment. The more hydrophobicity of the substrate the higher TOFreached. When the range of LogP_o/wof products is from1to2, higherconversion rate will be reached and close to the catalytic activity ofRu（tpp）OAc.（4） Catalyzing alcohol selective oxidation by bio-inspired hydrophobiccatalyst also gets high catalytic activity. The conversion rate of2-hydroxyacetophenone is much higher than the homogeneous catalysts, theyield reach65%after one hour. TOF also reached7951h^-1which is24-foldthan the homogeneous catalyst.