HOMOGENEOUS MODELS FOR HYDRODENITROGENATION CATALYSIS

Hydrodenitrogenation (HDN) catalysis is the process of removing nitrog en from petroleum feedstocks in the form of NH3 to provide more proces sable and environmentally compatible liquid fuels. In practice, HDN is carried out simultaneously with other catalytic hydrotreating reactio ns such as hydrodesulfurization (HDS), yet HDN is significantly less w ell-studied than HDS. This contribution provides an overview of the he terogeneous HDN process, then outlines various homogeneous models for hydrodenitrogenation catalysis including binding modes of HDN substrat es, catalytic hydrogenation processes and recent C--N bond cleavage re actions of nitrogen heterocycles. Emphasis is placed on aryloxide and alkoxide complexes of the early metals that afford some of the best ho mogeneous models for hydrodenitrogenation catalysis to date. (C) 1997 Elsevier Science Ltd.