Hydrodesulfurization – Homogeneous

Abstract

In spite of the large‐scale industrial applications of the hydrodesulfurization (HDS) process, and of the large number of studies of this reaction on heterogeneous catalysts, some aspects of the mechanisms involved are not yet fully understood. This article summarizes the most striking aspects of coordination and organometallic chemistry that are pertinent to the activation, hydrogenation, and desulfurization of thiophenes, in a systematic way, and inasmuch as possible in connection with the common knowledge and beliefs of the mechanisms of heterogeneous HDS catalysis. The binding of thiophenes to transition metals in molecular complexes, as well as the reactivity of such complexes in solution, is described in detail, with particular emphasis on reaction mechanisms. The examples presented are excellent molecular analogues of the species and reactions that are known or thought to intervene in heterogeneous catalysis, and thus this organometallic approach constitutes a good complement to surface and solid‐state chemistry studies and contributes to the understanding of this important reaction.