Highly active chromium-based selective ethylene tri-/tetramerization catalysts supported by PNPO phosphazane ligands.
Highly active chromium-based selective ethylene tri-/tetramerization catalysts supported by PNPO phosphazane ligands.
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DOI：
10.1039/c5dt00801h
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发表时间：
2015-05
影响因子：
4
通讯作者：
Yusheng Zhou;Hongfei Wu;Sheng Xu;Xue-Jin Zhang;M. Shi;Jun Zhang
中科院分区：
文献类型：
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作者：
Yusheng Zhou;Hongfei Wu;Sheng Xu;Xue-Jin Zhang;M. Shi;Jun Zhang
制备了以Ph2PN(R)P(Ph)OAr型PNPO磷烷配体为载体的新型Cr（iii）催化剂，这些催化剂经MMAO-3A活化后，具有较高的乙烯三/四聚反应活性和选择性。研究了配体取代对催化性能的影响。含n -环己基的PNPO磷烷配体负载的Cr预催化剂在35 bar和40℃条件下，以氯苯为溶剂，对有价的1-己烯（45.7%）和1-辛烯（39.4%）的总选择性为85.1%，活性为316.7 kg （g Cr h(-1)）。在甲基环己烷中，[Ph2PN((i)Pr)P(Ph)OPh]负载的预催化剂表现出较高的1-辛烯选择性（54.0%），在35 bar和40°C下的活性为73.3 kg (g Cr h(-1))（-1）。通过对配体主链的微调，这种基于PNPO磷烷的催化剂体系为精确理解配体变化对催化性能的影响提供了一种模式。
Novel Cr(iii) catalysts supported by PNPO phosphazane ligands of the type Ph2PN(R)P(Ph)OAr have been prepared, all of which, upon activation with MMAO-3A, are highly active in ethylene tri-/tetramerization with considerable selectivity. The effect of ligand substitution on the catalytic performance has been examined. The Cr precatalyst supported by the PNPO phosphazane ligand with an N-cyclohexyl achieved high activity of 316.7 kg (g Cr h(-1))(-1) and a high total selectivity of 85.1% towards valuable 1-hexene (45.7%) and 1-octene (39.4%) using chlorobenzene as the solvent at 35 bar and 40 °C. In methylcyclohexane, the precatalyst supported by [Ph2PN((i)Pr)P(Ph)OPh] exhibited a higher 1-octene selectivity (54.0%) with a considerable activity of 73.3 kg (g Cr h(-1))(-1) at 35 bar and 40 °C. With the fine-tuned ligand backbone, such a PNPO phosphazane-based catalyst system provides a mode for precise understanding of the impact of ligand variations on catalytic performance.