Molecular understanding of Re-based heterogeneous olefin metathesis catalysts

摘要

Olefin metathesis (OM) has always been a key reaction in industry since its discovery. Yet, it has become very popular in the last 10 years with the development of well-defined homogeneous catalysts, whose stability, selectivity and functional group tolerance have encouraged their use in the area of fine chemical synthesis and material science. In fact, it will probably lead to important commercial applications in a near future. Similarly, while OM has always been a cornerstone of the petrochemical industry since the sixties, it has also become more and more important in this past few years, because of the increase world demand in propene. Indeed, the yield of propene from crackers can be increased by associating olefin metathesis units to crackers in order to convert ethene into propene via cross-metathesis with 2-butenes. This is typically carried out with the Lummus process, which runs at relatively high temperatures, e.g. 400°C, using a catalyst based on WO3 dispersed on an oxide support.