The selective reaction of α-olefins with two ethylene molecules

一般性意见。α-烯烃是合成塑料、医药、大宗和精细化学品的重要原料。由乙烯（一种廉价且大量可用的C2结构单元）合成α-烯烃每年以百万吨规模进行，并且代表了均相催化在化学工业中最重要的应用之一。由乙烯选择性合成α-烯烃仅限于三种烯烃：1-丁烯、1-己烯和1-辛烯。所有这三个都是极其重要和应用的挑战。其他合成方案产生需要分离的α-烯烃的分布。对特定烯烃的兴趣很少与其在产品分布中的份额或比例相匹配。其中α-烯烃选择性地与乙烯反应的广泛适用的α-烯烃伸长反应将是高度期望的。此外，支链的引入在人造润滑剂的合成方面是有吸引力的。此外，支链α-烯烃是用于合成透明塑料和用作气体分离膜的单体。选择性支化的α-烯烃也可用于官能化反应，例如加氢裂化，一种以百万吨规模进行的反应。前期工作在发表于《科学》和《自然通讯》的初步工作中，我们介绍了新型催化α-烯烃合成。α-烯烃的伸长和支化在概念上是特别令人感兴趣的，因为它允许选择性合成各种α-烯烃，并且与已建立的由乙烯合成α-烯烃相比，首次提供了获得支化α-烯烃的途径。目标和工作计划。本论文的主要内容是：从机理上理解α-烯烃与两个乙烯分子的反应，特别是乙烯- α-烯烃-乙烯反应，并探索该反应在合成α-烯烃（烯烃合成）中的应用潜力。因此，提出了与两个主要意图有关的七个工作包。机制WP 1：实验工作，以了解插入序列。WP 2：中心金属的变化。WP 3：配体的变化。烯烃合成。WP 4：其他Ap-Imi-Ti络合物的共二聚体选择性。WP 5：乙烯向支链辛烷的四聚。WP 6：乙烯4-乙基己烯的聚合和共聚。WP 7：二烯与乙烯的选择性反应。拟议里程碑见第2.3.3节。这两个中心目标密切相关，只有在“对话”中才能获得概念上新颖的知识。

General remarks. α-Olefins are important starting materials for the synthesis of plastics, pharmaceuticals, bulk and fine chemicals. The synthesis of α-olefins from ethylene, an inexpensive and abundantly available C2 building block, is carried out in mega-ton scale annually and represents one of the most important application of homogeneous catalysis in the chemical industry. The selective synthesis of α-olefins from ethylene is restricted to only three olefins: 1-butene, 1-hexene, and 1-octene. All three are extremely important and applied diversely. Other synthesis protocols produce distributions of α-olefins that need to be separated. The interest of a specific olefin rarely matches with its share or proportion in the product distribution. A broadly applicable α-olefin elongation reaction, in which α-olefins react selectively with ethylene, would be highly desirable. In addition, the introduction of branches is attractive with regard of the synthesis of artificial lubricants. Furthermore, branched α-olefins are monomers for the synthesis of transparent plastics and as membranes for gas separation. Selectively branched α-olefins can also be of interest for functionalization reactions such as hydroformylation, a reaction carried out in mega-ton scale. Preliminary work. In published preliminary work, which appeared in “Science” and “Nature Communication”, we introduced novel catalytic α-olefin syntheses. The elongation and branching of α-olefins is conceptually especially interesting since it permits the selective synthesis of various α-olefins and in comparison to established synthesis of α-olefins from ethylene access to branched α-olefins is provided for the first time. Aims and work plan. The central intension of our proposed works are: Understanding the discovered reaction of α-olefins with two ethylene molecules specifically the ethylene- α-olefin-ethylene sequence mechanistically (mechanism) and to explore the potential of this reaction for the synthesis of α-olefins (olefin synthesis). Therefore, seven work packages are proposed that are related to the two main intentions. Mechanism. WP 1: experimental work to understand the insertion sequence. WP 2: variation of the central metal. WP 3: variation of the ligands. Olefin syntheses. WP 4: co-dimer selectivity of other Ap-Imi-Ti complexes. WP 5: tetramerisation of ethylene towards a branched octane. WP 6: polymerization and co-polymerization of ethylene 4-ethylhexene. WP 7: selective reactions of dienes with ethylene. The proposed milestones are listed in section 2.3.3. Both central aims are strongly connected and a conceptually novel quality of knowledge can only be obtained in “dialogue”.