Activity and stability studies of H-transfer reduction reactions of aldehydes and ketones over aluminium isopropoxide heterogenised catalysts

Aluminium isopropoxide Al(OiPr)3 immobilised on various mesoporous supports (SiO2, TiO2 and g-Al2O3) was tested for H-transfer reductions of various aldehydes and ketones in the presence of 2-propanol as a sacrificial agent. The heterogenised catalysts were characterised by N2 physisorption, XRD, SEM-EDX, FTIR and ICP-OES. The characterisation results show a successful grafting of the homogeneous aluminium isopropoxide catalyst, covalently bound to the solid surface, with high dispersion over the mesoporous supports. The heterogenised catalysts show an excellent catalytic activity with high selectivity towards the desired alcohol product, with performances that are comparable with those of the homogeneous Al(OiPr)3 catalyst. Al(OiPr)3 grafted on SiO2 shows higher activity compared to g-Al2O3 and TiO2 supported catalysts.