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The fabrication of low-cost, recyclable, reusable, and heterogeneous catalysts is of considerable significance for green chemistry. In this study, a nanocomposite catalyst, MCM-41-supported Zn–Co double metal cyanide (MCM-41@DMC), was prepared using the synchronous dropping method. Thereafter, the composition, crystal structure, complexing state, morphology, and thermal stability of the catalyst were characterised using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller analysis, and thermogravimetry. The effects of different organic ligands on the catalytic activity of samples were evaluated, and the results showed that ethyl acetoacetate exhibited the best catalytic activity owing to its ketone coordination. The use of the MCM-41 support was beneficial for improving the catalytic activity because it reduced the crystallinity and substantially increased the external specific surface area of the catalyst. The experimental results pertaining to the use of the MCM-41@DMC catalyst in the fabrication of polypropylene glycol showed that the conversion of propylene oxide and molecular weight reached 90.6% and 2900, respectively. This study provides a new strategy for the green synthesis of poly(propylene glycol) products. [ABSTRACT FROM AUTHOR]

A series of Au–silica (nanosphere) catalysts were prepared by in situ synthesis; highly dispersed gold nanoparticles (GNPs, 6.4 nm) were obtained, and catalytic tests showed good catalytic activity and epoxidation selectivity. To investigate the origin of the GNPs, the solids were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and other instruments. Some reaction parameters, such as solvent, oxidant concentration, catalyst concentration and reaction time, have been investigated and reaction conditions are optimized. [ABSTRACT FROM AUTHOR]

Abstract: A series of silver-doped vanadium phosphorus oxides (Ag-VPO) catalysts were prepared by in situ synthesis, the catalytic tests showed that silver component significantly increased the overall activity for the oxidation of styrene by tert-butyl hydroperoxide (TBHP). It is interesting that Ag-VPO catalysts show no epoxidation selectivity but good selectivity for benzaldehyde in this study. To investigate the origin of the silver effect, the solids were characterized using X-ray diffraction (XRD), Fourier transformed-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and other instruments, the (VO)2P2O7, β-VOPO4, Ag(V2P2O10) and Ag2(VO2)(PO4) phases were detected in all the Ag-VPO catalysts. This study also confirms that ratios of P/V play a crucial role in the activity and the selectivity of the catalyst, meanwhile, the other factors, such as solvent, oxidant concentration, reaction time, also have been investigated and reaction conditions are optimized. [Copyright &y& Elsevier]