Реферат: Experimental results showing the unique possibilities of modification of catalytic properties of homogeneous metallocene IVB Group catalysts in propylene polymerization under the action of triisobutylaluminum (TIBA) or in the presence of small additives of Lewis bases (LB) are presented. It has been shown that the preactivation of zirconocene dichlorides at low MAO excess (~ 102 mol/mol) followed by the activation with TIBA also at low molar TIBA excess to over metallocene (~ 102 mol/mol) gives rise to very active homogeneous catalysts for olefin polymerization. The approach allows a 10-100-fold decrease of MAO charges. Monomethylated zirconocene complexes with MAO as catalytic intermediates formed under preactivation conditions and the mixture of tetraisobutylalumoxane/polyisobutylalumoxane as cocatalysts formed at nearby stoichiometric amounts of TIBA and MAO were recognized as the key components of the analyzed catalytic systems. It has been shown for the first time that purposeful introduction of almost stoichiometric amounts of ternary amines to the L2MMe2/Ph3CB(C6F5)4/TIBA catalytic systems (L2MMe2  =  Ph2CCpFluMMe2 (M=Zr,  Hf), rac-Me2SiInd2ZrMe2) can result in an extremely high increase in the catalyst activity, the effect being most pronounced for hafnocenes in the presence of NPh3. It was also shown that TIBA in these catalytic systems acts as the reagent reducing stereoselectivity of the catalyst leading to the formation of stereoblock polypropylenes for Cs-symmetry catalysts. The reasons for the effects observed are discussed.

Библиографическая ссылка: Bravaya N.M. , Faingol’d E.E. , Sanginov E.A. , Panin A.N. , Babkina O.N. , Saratovskikh S.L. , Chukanova O.N. , Ryabenko A.G. , Ushakov E.N.
Modification of Catalytic Properties of Homogeneous Metallocene Catalytic Systems in Propylene Polymerization under Action of Triisobutylaluminum and Lewis Bases
Studies in Surface Science and Catalysis. 2006. V.161. P.77-86. DOI: 10.1016/s0167-2991(06)80437-4 Scopus OpenAlex

Идентификаторы БД:

Scopus:	2-s2.0-33846531638
OpenAlex:	W1606549392

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БД	Цитирований
OpenAlex	5
Scopus	6

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