Highly Active and Selective Nanoalumina-Supported Wilkinson's Catalysts for Hydroformylation of Styrene

Uniform nano-Al2O3 particles were functionalized with surface amine ligands to form GO/nano-Al2O3 (where G stands for dendrimer generation) and then grafted with first generation PAMAM (polyamidoamine) dendrimers to form Gl/nano-Al2O3. G0/nano-Al2O3 and G1/nano-Al2O3 were used to tether Wilkinson's catalyst (RhCl(PPh3)(3)) to produce heterogenized rhodium complex catalysts, named respectively as Fh/G0/nano-Al2O3 and Rh/G1/nano-Al2O3. Both Rh/G0/nano-Al2O3 and Rh/G1/nano-Al2O3 catalysts show much higher activity and selectivity for hydroformylation of styrene than RhCl(PPh3)(3) anchored on supports such as alpha-Al2O3, gamma-Al2O3, and SBA-15. An increase of regioselectivity was observed from Rh/G0/nano-Al2O3 to Rh/G1/nano-Al2O3, showing the positive dendrimer effect on promoting the selectivity of styrene hydroformylation.