Selective Oxidation and Hydrogenolysis Catalysts Based On Highly Dispersed, Supported Fe and Ta Oxides

Supported oxides are important catalysts in a number of industrial reactions. Unusual reactivity can arise for extremely highly isolated structures that have enhanced Lewis acidity, so there is a continued need for new methods to produce catalysts that maintain a highly dispersed structure at relatively high loadings of the active phase. In particular, this laboratory has recently synthesized highly dispersed Fe oxides on SiO₂ using the bulky and anionic FeEDTA- complex as a precursor in otherwise traditional incipient wetness impregnation syntheses.[1] This method leads to very high, likely atomic, dispersion, and concomitant high reactivity in low temperature alkane oxidation to alcohols and ketones with H₂O₂. In parallel, we have developed a route to highly dispersed Ta oxides via a calixarene ligand.[2] These catalysts lead to high reactivity and, in particular, high selectivity in alkene epoxidation with H₂O₂ and in hydrodenitrogenation reactions. The latter exhibits a new mechanism by which catalysts can remove N-atom contaminants from crude fuels with minimal H₂ consumption.

[1] D. Prieto-Centurion, J. M. Notestein, J. Catal. (2011) in press.

[2] N. Morlanes, J. M. Notestein, J. Catal. (2010) 275, 191-201