乙烯反应中的铁配合物催化剂:从概念到产业化

Iron Complex Catalysts in Ethylene Reactivity:from Concept to Commercialization

聚烯烃的核心是催化剂,地球上丰度最高的过渡元素铁的配合物在催化乙烯反应中展示了优异性能,本文综述了用于乙烯低聚与聚合的铁配合物催化剂的最新进展.通过调控所用配体的电子效应和空间位阻可以实现乙烯催化性能与所得聚合物微观结构的控制;铁催化剂具有独特的优势,不仅实现α-烯烃制备,而且可以制备高度线性聚乙烯包括制备窄分布的聚乙烯蜡.铁催化剂未来将在高附加值聚乙烯有巨大应用潜力.

Polyethylene andα-olefins have been major products in petrochemical industry,in which their catalysts have been recognized as key points within the industrial processes.The iron,the most abundant element of transition metals in the Earth’s crust,has attracted considerable attention from researchers due to its minimal price,low toxicity and favourable biocompatibility.Surprisingly,iron complexes as catalysts show excellent performance in the catalytic systems such as oligomerization or/and polymerization of ethylene.Relied on their electronic and steric influences of substituents within ligand compounds used,iron complexes not only show different catalytic activities of ethylene reactivity but also produce different products from oligomers with low molecular weights to polyethylenes with various molecular weights.In another word,the microstructures of the resulting products can be controlled by finely tuning the electronic effects and steric hindrance of the ligands used to achieve a variety of products with highly linear and molecular weight differences fromα-olefins and highly linear polyethylene.In addition,most polyethylenes obtained have been approved with narrow distributions,especially for some types of polyethylene wax.In this review,the progress of iron complex catalysts for ethylene oligomerization or/and polymerization is reviewed,indicating the effects of ligand frameworks and their modifications through using different substituents as well as the differences in the catalytic activities and the microstructural properties of the obtained products.It would be temporarily short of its interest and attractiveness in academy,however,its industrial application would drive funds and keep its further investigations.To enhance the living life of any science,the 2-(imino)phenanthroline-iron catalysts were used in ethylene oligomerization to successfully produceα-olefins in a 50 kt/y process by Sinopec Maoming Branch in September 2021,which promoted Sinopec to construct a further developed process with 200 kt/y in Tianjin at November of 2021.It is the first iron catalyst being used in the petrochemical industry,moreover,it is the first process for a full range ofα-olefins achieved in Asian area until now.Therefore,the iron complex catalysts are highly promising and useful in advanced products includingα-olefins,polyethylene wax and linear polyethylenes.