The oligomerisation of ethylene with chromium-based catalysts containing asymmetric BIMA (bis(benzimidazole)methylamine) ligands produces linear alpha olefins (LAOs) that follow an alternating distribution. The catalytic activity and the degree of alternation is affected by the different ligands; in particular variations at the backbone of the ligand affect the nature of the distribution. For certain catalysts a deviation from regular alternating behaviour is observed, whereby increased amounts of 1-hexene and 1-octene (up to 29 mol%) are obtained compared to the amount expected from the distribution analysis based on C₁₀–C₃₄ LAOs. This behaviour towards more selective oligomerisation to 1-hexene and 1-octene can be explained by varying probabilities of single and double ethylene insertion. The deviations will depend on the size of the metallacycle and are most pronounced early on during the metallacycle growth.

中文翻译：

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在不对称BIMA配体的铬催化乙烯低聚中从交替分布到选择性分布†

用含不对称BIMA（双（苯并咪唑）甲胺）配体的铬基催化剂将乙烯低聚，生成线性α-烯烃（LAOs），该烯烃遵循交替分布。催化活性和交替程度受不同配体的影响。特别是配体主链上的变化会影响分布的性质。对于某些催化剂，观察到偏离规则的交替行为，从而与基于C ₁₀ –C ₃₄的分布分析所预期的量相比，获得了更多的1-己烯和1-辛烯（最高29 mol％）。老挝。可以通过改变单乙烯和双乙烯插入的概率来解释这种向更具选择性的低聚为1-己烯和1-辛烯的低聚行为。偏差将取决于金属环的大小，并且在金属环生长的早期最明显。