【摘要】 以酚膦化合物为双齿配体,合成与表征了一系列单组分中性镍烯烃聚合催化剂。研究表明,酚膦配体结构显著影响中性镍的催化性能,酚氧邻位无取代基的(2-PPh2-C6H4O)Ni(Me)(Py)(3a)活性较低,向酚氧邻位引入叔丁基或苯基等位阻基团可大幅度提高(2-PPh2-C6H3(R)O)Ni(Me)(Py)(3b～3d)的催化效率,最高催化活性可达4.46×106g PE/(mol(Ni)·h)。同时,聚乙烯的分子量也可以通过取代基效应进行适度调控,使用酚氧邻位带有苯基或蒽基的催化剂(3c～3d)可获得较高分子量的聚乙烯。用供电子叔丁基替代二苯膦的一个苯环可提高催化活性中心镍原子的电子云密度,使辅助配体吡啶更容易离去,从而可在较低温度下引发乙烯聚合反应。此外,这类酚膦中性镍催化剂对极性基团具有较强的耐受性,可催化乙烯与极性5-降冰片烯-2-乙酸酯的共聚反应。更多还原

【Abstract】 A series of phosphinophenolate neutral nickel catalysts bearing pyridine as spectator ligands(2-P(R1)(R2)-C6H3(R)O)Ni(Me)(Py)(3a,R=H,R1=R2=Ph;3b,R=t-Bu,R1=R2=Ph;3c,R=R1=R2=Ph;3d,R=anthr,R1=R2=Ph;3e,R=R1=t-Bu,R2=Ph) have been synthesized and characterized by 1H,13C and 31P NMR.As a kind of single component catalysts,other than 3a they all showed a higher catalitic activty to ethylene polymerization reaction,and a high catalytic activity up to 4460 kg PE/(mol(Ni)·h) was achieved by introducing proper steric effection groups at ortho position of its phenoxy group(3c～3d).Molecular mass of the polymer can be adjusted by varying the substituents as the ortho-position of phenoxy group,and using catalysts 3c～3d with aryl substituents in ethylene polymerization reaction could produced higher molecular mass polymer.Catalyst 3e with a tert-butyl group at its phosphorous atom showed similar activity as that of catalyst 3b and was more readily initiated,producing polymers of lower molecular msses under the same conditions.Moreover,these catalysts were tolerant towards polar groups and able to catalyze copolymerization of ethylene with norbornene or its polar derivative 5-norbornene-2-yl acetate.更多还原