Ethylene/α-olefin copolymerization by various nonbridged (cyclopentadienyl)(aryloxy)titanium(IV) complexes -: MAO catalyst system
Ethylene/α-olefin copolymerization by various nonbridged (cyclopentadienyl)(aryloxy)titanium(IV) complexes -: MAO catalyst system
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DOI：
10.1016/s1381-1169(01)00196-0
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发表时间：
2001-10-01
影响因子：
--
通讯作者：
Imanishi, Y
中科院分区：
文献类型：
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作者：
Nomura, K;Oya, K;Imanishi, Y
配体在乙烯-1-己烯共聚反应中的作用（Ⅲ）（芳氧基）钛（Ⅳ）配合物，Cp ′ TiCl 2（OAr）[OAr = O-2，6-（Pr 2C 6 H3）-Pr-i和Cp ′ = C5 Me 5（1），1，3-（Bu 2C 5 H3）-Bu-t（2），（Bu 2C 5 H4）-Bu-t（3），1，3-Me 2C 5 H3（5），Cp（6）; OAr = O-2，6-Me_2C_6H_3，Cp' = C_5Me_5（7），1，3-（Bu_2C_5H_3）-Bu-t（8）]，并以[Me_2Si（C_5Me_4）（（NBu）-Bu-t）] TiCl_2（4）为参照。结果表明，1具有最高的催化活性，所得聚（乙烯-co-1-己烯）具有相对高的分子量和较窄的分子量分布（M-w = 29.5 × 10（4）~ 34.5 × 10（4），M-w/M-n = 1.74-1.88），且1-己烯含量相对较高（36.6- 43.5mol%）。在共聚反应中，α-烯烃和芳氧基的作用不仅使聚合物表现出高的催化活性，而且使聚合物具有相对高的分子量和较窄的多分散性，α-烯烃的引入也受到α-烯烃上取代基的影响。聚合温度和Al/Ti摩尔比对单体竞聚率没有影响，但单体序列分布和单体竞聚率取决于所用的Al_2O_3片段。尽管Cp-Ti-O的键角相当宽（约100 ° C），Cp-Ti-N在1-3中的内旋度（120.5度）比Cp-Ti-N在4中的内旋度（107.6度）高，1-己烯的引入量高，r（E）r（H）值比Cp-Ti-N在4中的小1-3，这可能是由于Cp-Ti-N中的苯环和芳氧基都具有灵活的内旋。(C)2001 Elsevier Science B. V.保留所有权利。
Effect of ligand in copolymerization of ethylene with 1-hexene by (cyclopentadienyl)(aryloxy)titanium(IV) complexes of the type, Cp'TiCl2(OAr) [OAr = O-2,6-(Pr2C6H3)-Pr-i and Cp' = C5Me5 (1), 1,3-(Bu2C5H3)-Bu-t (2), (Bu2C5H4)-Bu-t (3), 1,3-Me2C5H3 (5), Cp (6); OAr = O-2,6-Me2C6H3 and Cp' = C5Me5 (7),1,3-(Bu2C5H3)-Bu-t (8)], has been explored in the presence of MAO, and [Me2Si(C5Me4)((NBu)-Bu-t)]TiCl2 (4) was chosen as the reference. It was revealed that 1 exhibited the highest catalytic activity, and the resultant poly(ethylene-co-1-hexene)s possessed relatively high molecular weights with narrow molecular weight distributions (M-w = 29.5 x 10(4) to 34.5 x 10(4), M-w/M-n = 1.74-1.88), and contained 1-hexene in relatively high extents (36.6-43.5 mol%). Effect of both cyclopentadienyl and aryloxy groups plays an essential key role in the copolymerization not only to exhibit high catalytic activity but also to afford relatively high molecular weight copolymer with narrow polydispersity.It also turned out that a-olefin incorporation into the copolymer is highly affected by the substituents on the cyclopentadienyl group. The monomer reactivity ratios were not affected by both the polymerization temperature and Al/Ti molar ratios, but the monomer sequence distributions and the monomer reactivity ratios depended upon cyclopentadienyl fragment used. In spite of the rather wide bond angle of Cp-Ti-O (ca. 120.5 degrees) in 1-3 than that of Cp-Ti-N in 4 (107.6 degrees), a high level of 1-hexene incorporation and smaller r(E)r(H), value by 1-3 than those by 4 were attained, which would be due to the flexible internal rotation of both cyclopentadienyl and aryloxy groups. (C) 2001 Elsevier Science B.V. All rights reserved.