Catalysis Letters, Vol.149, No.12, 3370-3383, 2019
Catalytic Role of Pd(II) Ions in Mg-Al Hydrotalcites for the Oxidation of Styrene
Pd(II) ions were introduced into Mg0.7Al0.3(OH)(2)(CO3)(0.15)center dot mH(2)O through the co-precipitation of the corresponding nitrate salts at a constant pH value. The presence of Pd in the brucite-like layers affects an increased surface area and decreased crystal domain of the Mg-Al hydrotalcite catalysts. Pd(II) ions may exist in both intra- and extra- brucite-like layers and exhibit different roles in the oxidation of styrene with t-BuOOH, depending on the amount of palladium. The insertion of Pd(II) into the hydrotalcite lattice has significantly improved the catalyst stability. The highest conversion of styrene is about 80% for the production of styrene oxide and benzaldehyde at low temperatures. Graphic