Gongde Wu

Selective Oxidation of Glycerol with O2 Catalyzed by LDH Hosted Transition Metal Complexes

A series of Mg–Al layered-double hydroxides (LDHs) intercalated by sulphonato-Schiff base complexes were prepared for the selective oxidation of glycerol (GLY) with O2 as oxidant. The results revealed the LDH hosted complexes were effective catalysts, and their catalytic performance were closely related to the structures and composition of catalysts, the base environments of reaction mixtures as well as the reaction conditions. Among them, LDH hosted copper complex displayed the highest catalytic performance, and the GLY conversion could reach 82.5 with 86.1xa0% of the selectivity to glyceric acid (GLYAC). Moreover, the catalytic performance remained after being recycled seven times.Graphical AbstractLDH hosted transition metal complex catalysts were promising catalysts for the selective oxidation of GLY to glyceric acid with O2. The catalytic performance of catalysts and the product distribution were found to be closely related to the structures and composition of catalysts, the base environments of reaction mixtures as well as the reaction conditions. The best GLY conversion reached 82.5 with 86.1xa0% of the selectivity to GLYAC.

Environmental Benign Oxidation of Benzyl Alcohol Catalyzed by Sulphonato-Salphen–Chromium(III) Complexes Immobilized on MCM-41

AbstractThree amphiphilic sulphonato-salen–chromium(III) complexes immobilized on MCM-41 were prepared for the solvent-free selective oxidation of benzyl alcohol with 30xa0% hydrogen peroxide. The immobilized complexes were effective catalysts and exhibited much higher catalytic performance than their corresponding homogeneous analogues and immobilized lipophilic complexes. Under the optimum reaction conditions, benzyl alcohol conversion could reach 60.3xa0% with 100xa0% of the selectivity to benzaldehyde. In addition, the catalysts could be recycled at least five times.nGraphical AbstractThe immobilized amphiphilic sulphonato-salen–chromium(III) complexes were effective in the selective oxidation of benzyl alcohol due to the increased accessibility of oxidant to catalyst and reactant. The best benzyl alcohol conversion reached 60.3% with 100% of the selectivity to benzaldehyde.

Catalytic Roles of Metal Centers in the Selective Oxidation of Cyclohexanol by Cr(salten) Complexes Immobilized on MCM-41

A series of transition metal complexes of 3-[N,N′-bis-3-(salicylidenamino)ethyltriamine] (salten) immobilized on MCM-41 were prepared for the solvent and additive-free selective oxidation of cyclohexanol with 30xa0% hydrogen peroxide (H2O2). The immobilized complexes were effective catalysts and exhibited much higher catalytic performance than their homogeneous analogues. Moreover, the metal centers were found to play important roles in the catalytic performance of immobilized complexes. When the immobilized chromium complex was used as catalyst, the optimal cyclohexanol conversion could reach 90.5xa0% with 100xa0% of the selectivity to cyclohexanone. In addition, the catalytic performance remained after being recycled five times.Graphical AbstractOwing to the different 3d electronic numbers of metal centers, eight kinds of immobilized Schiff base complexes exhibited significantly different catalytic performance in the selective oxidation of cyclohexanol with 30xa0% H2O2. The optimal cyclohexanol conversion could reach 90.5xa0% with 100xa0% of the selectivity to cyclohexanone over immobilized chromium complex.