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The synthesis and polymerization study of novel transition metal catalysts.

机译:新型过渡金属催化剂的合成与聚合研究。

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摘要

The syntheses of two new titanium Ziegler-Natta catalysts [C5H 4(C6F5)]TiCl3 (9) and [C5H4(C6F5)]2TiCl 2 (10) have been developed with a pentafluorophenylcyclopentadienyl moiety. EPR measurements of 9/MAO and 10/MAO (MAO = methylaluminoxane) indicate that facile reduction of 9/MAO and 10/MAO to Ti (III) species occurs. It is suggested that the titanium complexes 9 and 10 with electron-withdrawing pentafluorophenyl substituents favor reduction during polymerizations. This is possibly the reason high activities and stereoregularities are seen with 9 for styrene, while poor activities are seen with 10 for ethylene. In general for zirconium compounds, the reduction potential is much lower compared to titanium compounds and may be the reason higher activities are seen with [C5H4(C6F5 )]2ZrCl2 (8).; Several Ni(II) α-diimine complexes [ArN=C(Nap)-C(Nap)=NAr]NiBr 2 (Nap = 1,8-naphthdiyl) (17, Ar = 2,4,6-trimethylphenyl; 18, Ar = 2-tBu phenyl; 19, Ar = 2-iPr phenyl) have been synthesized and examined for ethylene and propylene polymerization in combination with different aluminum co-catalysts. These complexes were synthesized via two distinct procedures and these are discussed. X-ray structural studies of complexes 17 and 18 have been carried out. Diethylalumnium chloride (DEAL), and 1,3-dichloro, 1,3-diisobutyldialuminoxane (DCDAO) show higher activities for ethylene and propylene polymerizations in combination with these Ni(II) α-diimine complexes than does MAO.; We have prepared two new unbridged bis(indenyl) zirconium complexes of the type (1-RInd)2ZrCl2 (where R= norbornyl ( 25) or diphenylmethyl (26)) and have studied their ability to polymerize ethylene and propylene in combination with MAO. The polymerization ability of these catalysts were tested, and the resulting activity and molecular weight of the resulting polymer can be controlled by using different bulky substituents on the indenyl ring. We propose that the use of a bulky aliphatic R group promotes hydride elimination while a sterically constrained aromatic substituent prevents hydride elimination from occurring during the polymerization. The lower polymerization ability of complexes 25 and 26 compared to (t-BuInd)ZrCl2 (27) could be explained by the bulky substituent shielding the metal center, and hindering the accessibility of the monomer to coordinate and insert into the Zr-polymer bond.
机译:两种新型的齐格勒-纳塔钛催化剂[C 5 H 4 (C 6 F 5 )的合成] TiCl 3 9 )和[C 5 H 4 (C 6 F 5 )] 2 TiCl 2 10 )具有五氟苯基环戊二烯基部分。 9 / MAO和 10 / MAO(MAO =甲基铝氧烷)的EPR测量表明, 9 / MAO和 10 < / MAO生成Ti(III)物种。提示具有吸电子五氟苯基取代基的钛配合物 9 10 在聚合过程中有利于还原。这可能是因为苯乙烯 9 具有较高的活性和立构规整性,而乙烯 10 具有较差的活性的原因。通常,锆化合物的还原电位比钛化合物低得多,这可能是[C 5 H 4 (C 6 F 5 )] 2 ZrCl 2 8 )。几种Ni(II)α-二亚胺配合物[ArN = C(Nap)-C(Nap)= NAr] NiBr 2 (Nap = 1,8-萘二基)( 17 18 ,Ar = 2-tBu苯基; 19 ,Ar = 2-iPr苯基)并检测了乙烯和丙烯聚合与不同的铝助催化剂结合使用。这些配合物是通过两种不同的方法合成的,并进行了讨论。已经对复合物 17 18 进行了X射线结构研究。二乙基氯化铝(DEAL)和1,3-二氯,1,3-二异丁基二铝氧烷(DCDAO)与这些Ni(II)α-二亚胺配合物结合使用对乙烯和丙烯的聚合反应显示出比MAO高的活性。我们准备了两种新的(1-RInd) 2 ZrCl 2 类型的未桥接双(茚基)锆配合物(其中R =降冰片基( 25 )或二苯甲基( 26 )),并研究了它们与MAO结合聚合乙烯和丙烯的能力。测试了这些催化剂的聚合能力,并且可以通过在茚基环上使用不同的大体积取代基来控制所得聚合物的活性和分子量。我们建议使用大体积的脂族R基团促进氢化物消除,而空间受限的芳族取代基防止在聚合过程中发生氢化物消除。与(t-BuInd)ZrCl 2 27 )相比,复合物 25 26 的聚合能力较低。可以通过屏蔽金属中心的笨重的取代基来解释,这阻碍了单体配位并插入Zr-聚合物键的可及性。

著录项

  • 作者

    Maldanis, Richard John.;

  • 作者单位

    University of Massachusetts Amherst.;

  • 授予单位 University of Massachusetts Amherst.;
  • 学科 Chemistry Inorganic.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 86 p.
  • 总页数 86
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 无机化学;
  • 关键词

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