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Catalyzed chain growth polymerisation of ethylene using lanthanidocenes/dialkylmagnesium: further developments and one pot synthesis of narrow dispersed high molecular weight fatty alcohols
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2020-08-25 , DOI: 10.1039/d0cy01451f
T. Chenal 1, 2, 3, 4, 5 , M. Drelon 1, 2, 3, 4, 5 , B. Marsh 1, 2, 3, 4, 5 , F. F. Silva 1, 2, 3, 4, 5 , M. Visseaux 1, 2, 3, 4, 5 , A. Mortreux 1, 2, 3, 4, 5
Affiliation  

Ethylene polymerisation on dialkylmagnesium using neodymocene based catalysts via catalyzed chain growth (CCG) has been studied with the aim to improve the performance of the overall catalytic/transfer process. A one pot in situ alkylation procedure has been developed, using commonly available neodymium salts and substituted cyclopentadienes for the catalyst synthesis. This method has been shown to be as efficient as the use of the classical system involving the pre-synthesized well-defined Image ID:d0cy01451f-t1.gif as a precursor. Further experiments conducted on the classical system have also shown that despite their well-known coordination properties, introducing polyethers in the reaction resulted in a tremendous enhancement of the productivity (up to ×800), while keeping the dispersity of the resulting product as low as 1.1. This enhancement is assigned to the result of a much higher dissociation of dialkylmagnesiums, leading first to a strong increase of the exchange rate within the magnesium partners, in conjunction with a dissociative effect on the [Nd–Mg] associated complexes, providing a concomitant concentration increase of the putatively mononuclear Image ID:d0cy01451f-t2.gif species responsible for the propagation step. Application to the synthesis of higher molecular weight fatty alcohols of the UNILIN™ range via direct oxidation by diluted O2 (20% in Ar) of the (polyethylenyl)magnesiums has been performed, giving rise to overall yields of up to 92%, the latter being dependent on the targeted molecular weights.

中文翻译:

镧系元素/二烷基镁催化乙烯的链增长聚合:窄分散高分子量脂肪醇的进一步发展和一锅合成

为了改进整个催化/转移过程的性能,已经研究了使用新茂基催化剂通过催化链增长(CCG)在二烷基镁上进行乙烯聚合。已经开发了一种单罐原位烷基化方法,使用通常可得的钕盐和取代的环戊二烯进行催化剂合成。事实证明,该方法与使用涉及预先合成的定义明确的经典系统一样有效。图片ID:d0cy01451f-t1.gif作为先驱。在经典体系上进行的进一步实验还表明,尽管具有众所周知的配位性能,但在反应中引入聚醚仍可极大地提高生产率(最高×800),同时保持所得产物的分散度低至1.1。这种增强作用归因于二烷基镁的高得多的解离,首先导致镁配偶体内的交换速率大大提高,同时对[Nd-Mg]相关复合物具有解离作用,从而提供了相应的浓度图片ID:d0cy01451f-t2.gif负责繁殖步骤的假定单核种增加。应用到UNILIN™范围的较高分子量的脂肪醇的合成通过已经通过稀释的O 2(在Ar中占20%)的镁进行了直接氧化,使总收率高达92%,后者取决于目标分子量。
更新日期:2020-10-19
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