Understanding the Hydrodenitrogenation of Heteroaromatics on a Molecular Level

The cleavage of recalcitrant C–N linkages in heteroaromatic molecules is a critical component of hydrodenitrogenation (HDN) reactions, the processes by which N atoms are removed from crude fuels. C–N bond cleavage of heteroaromatics with traditional HDN catalysts such as sulfided Ni/Mo-Al 2 O 3 and Ni/W-Al 2 O 3 requires aggressive conditions to hydrogenate the heterocyclic rings and often unnecessarily saturates the carbocyclic rings as part of the C–N cleavage process. In contrast, small-molecule models have illustrated selective hydrogenation of the heterocyclic ring, providing mechanistic insight into HDN processes and inspiring the design of new, more selective HDN catalysts.