Polyketone (PK) has attracted wide attention owing to its direct utilization of carbon monoxide, excellent properties, and photodegradation performance. However, the commercialized PK is produced using Pd-based catalysts, which accounts for the largest part of the production cost. Herein, [Ni(2-tol)(PPh₃)(N,O)] is used as the main catalyst for its high productivity and good tolerance to CO. Effects of the cocatalyst (Ni(COD)₂), the aging method in CO atmosphere, and the polarity of solvent are investigated. When Ni(COD)₂ is employed as the cocatalyst, the catalytic activity and molecular weight of PK are increased by 29% and 42.6%, respectively. Aging of catalyst system with Ni(COD)₂ in CO atmosphere leads to significant decrease in activity and molecular weight, while aging has almost no effect on the copolymerization without Ni(COD)₂. Different catalytic mechanisms are proposed for the catalyst system with and without cocatalyst. Furthermore, it is found that the polar solvent (CH₂Cl₂) significantly increases the activity by 119.2% compared to that in the nonpolar solvent (toluene). However, the thermal stability of the catalyst is much better in toluene. The study on the understanding of catalytic mechanism and improvement of activity will promote the practical application of nonprecious metal catalysts for preparation of PK.

中文翻译：

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乙烯和一氧化碳交替共聚镍基催化剂的研究：助催化剂和溶剂的极性

聚酮（PK）因其直接利用一氧化碳、优异的性能和光降解性能而受到广泛关注。然而，商业化的 PK 是使用 Pd 基催化剂生产的，占生产成本的最大部分。本文以[Ni(2-tol)(PPh ₃ )(N,O)]为主要催化剂，具有高产率和良好的CO耐受性。助催化剂(Ni(COD) ₂ )的影响，时效方法在 CO 气氛中，研究了溶剂的极性。当Ni(COD) ₂用作助催化剂时，PK的催化活性和分子量分别提高了29%和42.6%。Ni(COD) _{2催化剂体系的老化}在CO气氛中导致活性和分子量显着降低，而老化对没有Ni(COD) ₂的共聚几乎没有影响。对于有和没有助催化剂的催化剂体系，提出了不同的催化机理。此外，发现极性溶剂（CH ₂ Cl ₂）与非极性溶剂（甲苯）相比，活性显着提高了119.2%。然而，催化剂在甲苯中的热稳定性要好得多。了解催化机理和提高活性的研究将促进非贵金属催化剂在制备PK中的实际应用。