[O(S),O=P]型配体修饰的单氯单茂锆催化剂的高温乙烯聚合

Ethylene Polymerization by Monochloro Non-Bridged Half-Metallocene-type Zirconium Complexes Containing Phosphine Oxide-(thio) phenolate Chelating Ligands as Catalyst at High Temperature

以Ph3CB(C6F5)4/iBu3Al作为助催化体系,研究了单氯半茂型催化剂,ClCp'Zr[X-2-R1-4-R2-6-(Ph2PO)C6H2]2(Cp'=C5H5,a:X=O,R1=Ph,R2=H;b:X=O,R1=F,R2=H;c:X=O,R1=tBu,R2=H;d:X=O,R1=R2=tBu;e:X=O,R1=SiMe3,R2=H;f:X=S,R1=SiMe3,R2=H;Cp'=C5Me5;g:X=O,R1=SiMe3,R2=H)的乙烯高温(50~125℃)聚合行为。结果表明,催化剂a^d可在高温(50~100℃)下高效引发乙烯聚合,最佳反应温度为75℃。适当增大R1取代基的位阻或引入吸电子取代基均有利于提高催化活性。三甲基硅烷基取代的催化剂e耐高温性能较催化剂a^d大大提升,在100℃时,乙烯聚合活性可达5628 kg/(mol Zr·h)。金属中心的配位原子及茂环上取代基团的改变对催化活性和聚合物的相对分子质量分布有一定的影响。

Ethylene polymerizations were explored by monochloro half-zirconocene complexes containing phosphine oxide-（thio）phenolate chelating ligands of the type, CICp＇Zr[X-2-R^1-4-R^2-6-（ （Ph2P=O）C6H2 ]2 （Cp＇ =C5H5, a：X=O, R^1 =Ph, R^2 =H; b：X=O, R^1 =F, Rz =H; c：X=O, R^1 =＇Bu, R^2 =H; d：X= O, R^1 =R^2 =＇Bu; e：X=O, R^1 =SiMe3, R^2 =H; f.X =S, R^1 =SiM%, RE =n; Cp＇ =CsMes, g：X =O, R^1 = SiMe3, RE = H） in the presence of Ph3 CB （C6F5 ）4/iBuaA1 as co-catalyst at high temperature （50 125 ℃ ）. As reveled by the polymerization results, under optimized reaction temperature of 75 ℃, complexes a ~ d were efficient ethylene polymerization catalysts under high temperature（50 -100 ℃ ）. Catalytic activity was improved by increasing the steric hulk of R^1 substituent or the introduction of electron withdrawing groups at the same position. The occurrence of trimethylsilyl rendered a greatly improved temperature resistance for catalyst e than those of catalysts a ~ d, exhibiting an ethylene polymerization activity of 5628 kg/（ mol Zr. h） under 100 ℃ optimized reaction temperature. The variation of coordinated atom or the substituents at the Cp moiety had certain influences upon the catalytic activity and the PDI of the resulting polymer material.