| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 65679 | Journal of Molecular Catalysis A: Chemical | 2013 | 5 Pages |
•Multimetallic catalysts with hydrophobic supports were prepared.•They efficiently catalyzed oxidative esterification of MAL with CH3OH and O2 to MMA.•High MAL conversion and MMA selectivity were obtained in mild reaction condition.•These catalysts proved to be stable and recyclable.
The direct oxidative esterification of methacrolein (MAL) with methanol and oxygen to methyl methacrylate (MMA) was carried out over Pb and Bi-doped hydrophobic styrene-divinyl benzene copolymer (SDB) supported Pd catalyst under mild conditions. The Pd–Pb–Bi/SDB catalyst showed higher activity than bimetallic Pd–Pb/SDB and Pd–Bi/SDB, and much higher than monometallic Pd/SDB catalyst and hydrophilic catalysts. The multi-metallic catalysts were prepared through step impregnation method and characterized by N2 adsorption–desorption isotherm, environment scanning electron microscope (ESEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that addition of Pb and Bi to Pd catalyst produced an important decrease in the metallic particle size, and the intermetallic Pd3Pb and PdBi crystals were found in the multi-metallic catalysts, which facilitate the excellent performance of multi-metallic catalyst.
Graphical abstractCatalytic activities of Pd catalysts with hydrophobic SDB as carrier were higher than Pd3/γ-Al2O3 and Pd3/SiO2 since the hydrophobicity of SDB can prevent generated water covering the active sites. Catalytic performance of tri-metallic catalysts with Pb and Bi as promoters was higher than mono-metallic catalyst Pd3/SDB.Figure optionsDownload full-size imageDownload high-quality image (177 K)Download as PowerPoint slide
