Improvement of catalytic activity for α-diimine nickel complex with active sites stabilized by bulky boron counterions at elevated temperature,Applied Organometallic Chemistry

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Improvement of catalytic activity for α-diimine nickel complex with active sites stabilized by bulky boron counterions at elevated temperature
Applied Organometallic Chemistry ( IF 3.7 ) Pub Date : 2022-01-12 , DOI: 10.1002/aoc.6599
Xueer Wang ₁ , Zhongwei Feng ₁ , Wenqi Guo ₁ , Wentao Zhong ₁ , Xiaoyu Liu ₁ , Cheng Wang ₁ , Zhisheng Fu ₁ , Zhiqiang Fan ₁

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Three α-diimine Ni (II) catalysts (Cat.1, Cat.2 and Cat.3) were synthesized and investigated for ethylene polymerization using alkyl aluminum and organoboron compounds as binary cocatalyst. The effects of different alkyl aluminum and boron complexes on ethylene polymerization catalyzed by Cat.1, Cat.2, and Cat.3 were studied. The sodium tetrakis[3,5-bis (trifluoromethyl)phenyl]borate (NaBArF) was found to have best promotion for the catalytic activity of Cat.1, compared to negative effect of dimethylanilinium tetrakis (pentafluorophenyl)borate (TTB) and trityl tetrakis (pentafluorophenyl)borate (AB). All the three catalysts showed higher catalytic activity when NaBArF was introduced into the catalytic system, especially for Cat.3 (increased by 41.3% at 70°C). There was still minor increase of the catalytic activity for Cat.2 which have much better thermostability than Cat.3. The charging sequence of NaBArF and the [B]/[Ni] ratio have significant effects on the catalytic activity. The better catalytic performance of Cat.1/AlEt₂Cl/NaBArF could be explained by its ability to raise the number of active centers. Namely, the molar percentage of active centers of Cat.1/AlEt₂Cl/NaBArF was still above 30%, which was 1.7 times that of Cat.1/AlEt₂Cl even if polymerization ran up to 30 min based on 2-thiophenecarbonyl chloride (TPCC) quench-labeling method. Lower [Al]/[Ni] ratio but more active centers and longer active centers lifetime of this binary cocatalyst is promising for improving the activity of ethylene polymerization industrially at elevated temperature.

中文翻译：

在高温下通过大块硼反离子稳定活性位点提高 α-二亚胺镍络合物的催化活性

合成了三种α-二亚胺 Ni (II) 催化剂（Cat.1、Cat.2和Cat.3），并研究了使用烷基铝和有机硼化合物作为二元助催化剂的乙烯聚合反应。研究了不同烷基铝硼配合物对Cat.1、Cat.2、Cat.3催化乙烯聚合的影响。与四(五氟苯基)硼酸二甲基苯胺 ( TTB)的负面影响相比，发现四[3,5-双(三氟甲基)苯基]硼酸钠 ( NaBArF ) 对Cat.1的催化活性具有最佳促进作用和四（五氟苯基）硼酸三苯甲基酯（AB）。将NaBArF引入催化体系后，三种催化剂均表现出更高的催化活性，尤其是Cat.3（在 70°C 时提高了 41.3%）。Cat.2的催化活性仍有小幅增加，其热稳定性比Cat.3好得多。NaBArF的充电顺序和[B]/[Ni]比对催化活性有显着影响。Cat.1 / AlEt ₂ Cl/ NaBArF的催化性能更佳可以通过它提高活跃中心数量的能力来解释。即Cat.1 / AlEt ₂ Cl/ NaBArF的活性中心摩尔百分比仍然在 30% 以上，是Cat.1 / AlEt ₂ Cl 的 1.7 倍，即使基于 2-噻吩羰基聚合反应时间长达 30 分钟。氯化物 (TPCC) 淬灭标记法。这种二元助催化剂具有较低的[Al]/[Ni]比、更多的活性中心和更长的活性中心寿命，有望在工业上提高乙烯聚合在高温下的活性。

更新日期：2022-01-12

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