Immobilization and activation of 2,6-bis(imino)pyridyl Fe, Cr and V precatalysts using a MgCl2/AlRn(OEt)3−n support: Effects on polyethylene molecular weight and molecular weight distribution

Huang, R Rubin; Kukalyekar, Nileshkumar; Koning, Cor E.; Chadwick, John C.

doi:10.1016/j.molcata.2006.07.030

Cited by 41 publications

(38 citation statements)

References 48 publications

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“…Supported systems have also been examined using alternative activators [154,155,156,157,158,159] . For example, silica-and alumina-supported samples 5 have been activated with Al( i -Bu) 3 to afford highly active, thermally robust catalysts [154] .…”

Section: Supported Catalystsmentioning

confidence: 99%

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Gibson¹,

Solan²

2008

Topics in Organometallic Chemistry

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This chapter describes the brief history of iron or cobalt catalysts for olefin polymerisation and oligomerisation. Since the discovery in 1998 that 2,6-bis(imino)pyridine iron and cobalt halides, on activation with MAO, can convert ethylene to highly linear polyethylene, numerous reports have been concerned with ligand modification, mechanisms for precatalyst activation, identifying the active species and understanding the mode of propagation/chain transfer. In addition, heterogenisation of this class of catalysts, their incorporation into macrocycles/ polymers and their use in reactor blending/tandem catalysis has seen some important developments; alternative ligand architectures that can support active iron and cobalt catalysts are also discussed as are different types of olefinic monomer.

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Section: Supported Catalystsmentioning

confidence: 99%

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Gibson¹,

Solan²

2008

Topics in Organometallic Chemistry

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“…Huang et al [43] successfully immobilized 2,6-bis(imino) pyridyl Fe, Cr, and V precatalysts on MgCl 2 /AlR n (OET) 3−n supports. They studied the effects of different transition-metals on catalytic activity, molecular-weight, and molecular-weight distribution of the resultant PE, and found that the activities of heterogeneous systems were higher than those of homogeneous systems.…”

Section: Late-transition-metal Catalysts Immobilized On Mgcl 2 Supportsmentioning

confidence: 99%

Recent progress in immobilization of late-transition-metal complexes with diimine ligands for olefin polymerization

Jiang

et al. 2013

Chin. Sci. Bull.

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Late-transition-metal (LTM) catalysts are a family of very flexible ethylene polymerization catalysts because their catalytic performance can be easily adjusted by modifying the ligand structure. Their less oxyphilicity character, which may promote the production of copolymers from ethylene and polar comonomers, is another aspect that attracts much attention in both academic and industrial fields. The immobilization of LTM catalysts on spherical supports is a crucial step prior to their use in the industrial processes of gas-phase or slurry polymerizations. This paper reviews recent developments in supported LTM catalysts for olefin polymerization, and summarizes loading methods and mechanisms of the immobilization of LTM catalysts on inorganic, organic, and inorganic-organic materials, and the effects of immobilization on catalytic activity, polymerization mechanism, and polymer morphology. [22,23] are applied to olefin polymerization. The products obtained using such catalysts can be changed from polyethylene (PE) to oligomers by tuning the steric and electronic properties of the ligands [24]. Bulky complexes can produce high-molecular-weight branched PE, without the addition of α-olefin comonomers, in the presence of methylaluminoxane (MAO). Some bulky catalysts with special backbone such as camphyl and acenaphthyl show highly thermal stability and good control ability for olefin polymerization [25]. Late transition-metals are more suitable for the copolymerization of ethylene with commercial polar olefins because of their better tolerance of polar functional groups. Only amorphous polymers can be obtained if the polymerization is catalyzed by homogeneous catalysts, inevitably leading to reactor fouling in industrial units. To meet the requirements of continuous industrial gas-phase or slurry polymerization units, a crucial step for the industrialization of LMT catalysts is the immobilization of such catalysts on spherical supports to obtain morphologically uniform polymer particles. late-transition-metal complexes, diimine, immobilization, olefin polymerization

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“…Among the transition metal complexes having a bis(imino) pyridine backbone, the bis(imino)pyridinevanadium(III) complexes have been investigated, because these combined with MAO show a significant activity for the polymerization or oligomerization of ethylene 6)～16) . Moreover, as remarkable properties, these complexes promoted the copolymerization of ethylene and α-olefin 6) , and the supported catalysts using a modified magnesium chloride can produce high-molecular weight polyethylene 13) . When metal complexes are used for most of the industrial polymerization processes, they must be immobilized on carriers.…”

Section: Introductionmentioning

confidence: 99%