|Title||Tandem Catalysis by Palladium Nanoclusters Encapsulated in Metal-Organic Frameworks|
|Publication Type||Journal Article|
|Year of Publication||2014|
|Authors||Li, XL, Guo, ZY, Xiao, CX, Goh, TW, Tesfagaber, D, Huang, WK|
|Type of Article||Article|
|Keywords||acetal, acetalization, aerobic, bifunctional catalysts, cascade reactions, formic-acid, gold clusters, heterogeneous catalyst, hydrogen-peroxide, linker substitution, multifunctional catalysts, oxidation, primary alcohols, selective oxidation, solid acid, tandem synthesis, UiO-66|
A bifunctional Zr-MOF catalyst containing palladium nanoclusters (NCs) has been developed. The formation of Pd NCs was confirmed by transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS). Combining the oxidation activity of Pd NCs and the acetalization activity of the Lewis acid sites in UiO-66-NH2, this catalyst (Pd@UiO-66-NH2) exhibits excellent catalytic activity and selectivity in a one-pot tandem oxidation-acetalization reaction. This catalyst shows 99.9% selectivity to benzaldehyde ethylene acetal in the tandem reaction of benzyl alcohol and ethylene glycol at 99.9% conversion of benzyl alcohol. We also examined various substituted benzyl alcohols and found that alcohols with electron-donating groups showed better conversion and selectivity compared to those with electron-withdrawing groups. We further proved that there was no leaching of active catalytic species during the reaction and the catalyst can be recycled at least five times without significant deactivation.
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