Ethylene polymerization and ethylene/hexene copolymerization by vanadium(III) complexes bearing bidentate phenoxy-phosphine oxide ligands
Ethylene polymerization and ethylene/hexene copolymerization by vanadium(III) complexes bearing bidentate phenoxy-phosphine oxide ligands
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DOI：
10.1002/pola.26963
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发表时间：
2013-12
期刊：
影响因子：
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通讯作者：
Sen Zhang;Ling-Pan Lu;Ying-Yun Long;Yue-sheng Li
中科院分区：
文献类型：
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作者：
Sen Zhang;Ling-Pan Lu;Ying-Yun Long;Yue-sheng Li
合成了一系列含双齿苯氧基氧膦[O，P=O]配体的钒(III)配合物，(2-R-1-4-R-2-6-Ph2P=O-C6H2O)VCl2(THF)(2)(2a：R-1=R-2=H；2b：R-1=F，R-2=H；2c：R-1=TBU，R-2=H；2d：R-1=Ph，R-2=H；2e：R-1=R-2=Me；2f：R-1=R-2=TBU；2G：R-1=R-2=CMe2Ph)是在过量的三乙胺存在下，向VCl3(THF)(3)中滴加1当量的配体得到的。在相同的条件下，VCl3(THF)(3)加入到2.0当量的配体中，得到了含有两个[O，P=O]配体(3c，3f)的钒(III)配合物。用红外光谱、质谱学和元素分析对其结构进行了表征。化合物2c和3c的结构经X-射线单晶分析进一步确证。在Et2AlCl和三氯乙酸乙酯的活化下，这些配合物即使在高反应温度(70℃)下仍表现出高催化乙烯聚合活性(高达26.4 kg PE/mmol(V)·h.bar)，并生成单峰分子量分布的高分子量聚合物。此外，结构优化后的配合物对乙烯/1-己烯共聚合表现出较高的催化活性。通过改变催化剂的结构和反应参数，如Al/V摩尔比、共聚单体投料浓度、反应温度等，可以在较大范围内控制催化剂的活性、共聚单体的掺入量和聚合物的相对分子质量。根据~(13)C核磁共振波谱测定了单体竞聚率r(E)和r(H)，表明这些配合物在共聚反应中优先选择乙烯而不是1-己烯。(C)2013年威利期刊公司。
A series of novel vanadium(III) complexes bearing bidentate phenoxy-phosphine oxide [O,P=O] ligands, (2-R-1-4-R-2-6-Ph2P=O-C6H2O)VCl2(THF)(2) (2a: R-1 = R-2 = H; 2b: R-1 = F, R-2 = H; 2c: R-1 = tBu, R-2 = H; 2d: R-1 = Ph, R-2 = H; 2e: R-1 = R-2 = Me; 2f: R-1 = R-2 = tBu; 2g: R-1 = R-2 = CMe2Ph) have been synthesized by adding 1 equiv of the ligand to VCl3(THF)(3) dropwise in the presence of excess triethylamine. Under the same conditions, the adding of VCl3(THF)(3) to 2.0 equiv of the ligand afforded vanadium(III) complexes bearing two [O,P=O] ligands (3c, 3f). All the complexes were characterized by FTIR and mass spectra as well as elemental analysis. Structures of complexes 2c and 3c were further confirmed by X-ray crystallographic analysis. On activation with Et2AlCl and ethyl trichloroacetate, these complexes displayed high catalytic activities for ethylene polymerization (up to 26.4 kg PE/mmol(V).h.bar) even at high reaction temperature (70 degrees C) indicative of high thermal stability, and produced high molecular weight polymers with unimodal molecular weight distributions. Additionally, the complexes with optimized structure exhibited high catalytic activities for ethylene/1-hexene copolymerization. Catalytic activity, comonomer incorporation, and polymer molecular weight can be controlled in a wide range via the variation of catalyst structure and the reaction parameters such as AI/V molar ratio, comonomer feed concentration, and reaction temperature. The monomer reactivity ratios r(E) and r(H) were determined according to C-13 NMR spectra, which indicated these complexes preferred ethylene to 1-hexene in the copolymerization. (c) 2013 Wiley Periodicals, Inc.