10485-09-3Relevant articles and documents
Fry
, p. 2025 (1967)
PROCESS FOR PRODUCING A BIPHENYL METALLOCENE COMPLEX
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Paragraph 0034; 0036, (2021/10/11)
The invention relates to a process for preparing a boronic anhydride compound of formula (1), wherein, R1 - R4 are substituents as defined in the disclosure and 'B' stands for the element boron. The invention also describes a process of using the boronic anhydride of formula (1), to prepare a biphenyl metallocene complex of formula (4), wherein, R1 to R10, are substituents as defined in the disclosure; and wherein 'M' is a transition metal element, 'Q' is an halide anion, and 'P' is the valency of the transition metal element 'M' and indicates the number of halide anion present. In addition, the invention further describes a process of purifying the metallocene complex of formula (4) so as to render the overall metallocene complex synthesis process environmentally sustainable as well as cost effective by minimizing waste effluents.
Unbridged 1- and 2-substituted bis(silylindenyl) zirconium(IV) and hafnium(IV) dichloride complexes as catalyst precursors for ethylene polymerization
Abdelbagi, Mohamed E.M.,Alt, Helmut G.
, p. 284 - 295 (2017/09/20)
Twelve unbridged metallocene dichloride complexes of the types [1-(4-XC6H4SiMe2)-η5-Ind]2MCl2 and [2-(4-XC6H4SiMe2)-η5-Ind]2MCl2 (X = Me, MeO, F; M = Zr, Hf) with differently 1- and 2-substituted indenyl ligands have been synthesized, characterized and applied for catalytic ethylene polymerization. After activation with methylaluminoxane (MAO), all complexes are catalysts for ethylene polymerization. However, in nearly all cases, the species with the silyl substituent in the 1-position show much higher activities than those with the same substituent in 2-position of the indenyl moiety. For instance, the MAO activated complex bis(η5-1-(dimethyl-4-tolylsilyl)idenyl) zirconium(IV) dichloride (3), displayed an almost five times higher activity (3980 kg PE/mol cat.h) than the isomeric bis(η5-2-(dimethyl-4-tolylsilyl)indenyl) zirconium(IV) dichloride (19)/MAO catalyst (870 kg PE/mol cat.h). The same trend was observed for the para-fluorophenyl silyl indenyl complexes 23 and 17. This behavior may be explained in a way that the same silyl substituent in position 2 can exert more steric hindrance around the metal center compared to the 1-substituted analogues. The GPC characterization of the produced polyethylenes showed that some of the resins have a bimodal molecular weight distribution indicating at least two different active sites that are involved in the polymerization process.