Highly active and selective nanoalumina-supported Wilkinson's catalysts for hydroformylation of styrene

Abstract

Uniform nano-Al2O3 particles were functionalized with surface amine ligands to form G0/nano-Al2O3 (where G stands for dendrimer generation) and then grafted with first generation PAMAM (polyamidoamine) dendrimers to form G1/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 Rh/G0/nano-Al2O3 and Rh/G1/nano-Al2O 3. Both Rh/G0/nano-Al2O3 and Rh/G1/nano-Al 2O3 catalysts show much higher activity and selectivity for hydroformylation of styrene than RhCl(PPh3)3 anchored on supports such as α-Al2O3, γ-Al 2O3, and SBA-15. An increase of regioselectivity was observed from Rh/G0/nano-Al2O3 to Rh/G1/nano-Al 2O3, showing the positive dendrimer effect on promoting the selectivity of styrene hydroformylation. © 2009 American Chemical Society.