Metallocene Activation by Solid Acids

McDaniel, Max P.; Jensen, Michael D.; Jayaratne, Kumindini; Collins, Katherine; Benham, Elizabeth; McDaniel, Neal D.; Das, Pralay; Martin, Joel L.; Yang, Qing; Thorn, M; Masino, Albert P.

doi:10.1002/9783527621668.ch7

Cited by 22 publications

(56 citation statements)

References 19 publications

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“…As more metal is added the turnover declines. Hogan first observed this behavior [5] for Phillips catalysts and it has since been found for metallocene catalysts as well [37,38].…”

Section: Influence By Physical Characteristics Of the Support 221 The Influence Of Surface Area And Surface Coverage On Activitymentioning

confidence: 87%

“…However, the addition of electron-withdrawing anions to alumina increases the acidity of both Lewis and Bronsted sites [74]. These anions include halides, sulfate, phosphate, triflate, trifluoroacetate, and many others.…”

Section: Attachment and Ligation On Silica And Aluminamentioning

confidence: 99%

“…For example, neither silica nor alumina are known as particularly strong acids, but the combination, silica-alumina, usually displays very strong acidity. Other examples include silica-titania [3,75], silica-zirconia [3,76], and alumina-boria [3,77,78]. The combination can be obtained through cogellation of the two oxides, or by coating, that is, depositing one oxide on the other.…”

Section: Ligation On Mixed Oxide Supportsmentioning

confidence: 99%

“…LCB is further discussed in the sections below [79][80][81][82]. Metallocene catalysts also display higher activity when supported on mixed oxides [83]. Whereas silica produces no activity, and alumina produces minimal activity, the silica-aluminas can produce ten times the activity of alumina.…”

Section: Ligation On Mixed Oxide Supportsmentioning

confidence: 99%

“…However, 25 years ago Chevron-Phillips Chemical (CPC) introduced another commercial family of metallocene activators. In this system, the Lewis acid is an acidic solid oxide support [37,38]. In addition, an aluminum alkyl, such as triethylaluminum, is added to alkylate the metallocene halide.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of Support Effects on Phillips and Metallocene Catalysts

Yang

McDaniel

2021

Catalysts

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Both metallocene and Phillips chromium catalysts are used in the commercial manufacture of polyethylene. Unlike most other commercial metallocene systems, the Chevron Phillips Chemical (CPC) platform does not use methylaluminoxane or fluoroorganic boranes. Instead, the support itself serves to activate (ionize) the metallocenes, which then polymerize ethylene at high activity. Most of these solid acid supports can also be used to anchor Cr to make a Phillips catalyst. This provides an interesting opportunity to compare the polymerization responses by these two disparate systems, Phillips Cr and CPC metallocene, when supported on the same solid acid carriers. In this study, both chromium oxide and several metallocenes were deposited onto a variety of solid oxides, under a variety of conditions, and the resulting support effects were observed and compared. Although using seemingly different chemistries, the two catalyst systems exhibited a surprising number of similarities, which can be attributed to the acidity and porosity of these diverse supports.

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“…As more metal is added the turnover declines. Hogan first observed this behavior [5] for Phillips catalysts and it has since been found for metallocene catalysts as well [37,38].…”

Section: Influence By Physical Characteristics Of the Support 221 The Influence Of Surface Area And Surface Coverage On Activitymentioning

confidence: 87%

Section: Attachment and Ligation On Silica And Aluminamentioning

confidence: 99%

Section: Ligation On Mixed Oxide Supportsmentioning

confidence: 99%

Section: Ligation On Mixed Oxide Supportsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparison of Support Effects on Phillips and Metallocene Catalysts

Yang

McDaniel

2021

Catalysts

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Single‐Site Catalysts

Heurtefeu

Vaultier

Leino

et al. 2012

Encyclopedia of Polymer Science and Technology

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The recent rapid development of organometallic single‐site catalysts (SSCs) has revolutionized polyolefin research and permitted the production of new specialty polymers and commodity polyolefins with improved properties. These well‐defined catalyst systems generally consist of a transition metal atom, such as titanium, zirconium, hafnium, iron, nickel, or palladium, complexed with an organic ligand set and an initiating group. In most cases, activation with methylaluminoxane or compounds bearing a weakly coordinating anions generates cationic‐active species responsible for olefin coordination and polymer chain growth. Representative examples of SSCs include the bis(cyclopentadienyl) or bis(phenoxyimine)‐type group 4 catalysts as well as the diimine complexes of nickel and palladium. By variation of the organic ligand and thus the steric and electronic environment of the metal center, these catalysts can be tailored to control the olefin polymerization reaction in an unprecedented fashion. Almost any vinyl monomer, irrespective of molecular weight or steric hindrance, can be polymerized by choosing the proper catalyst. Virtually all feasible poly(α‐olefin) microstructures ranging from atactic to isotactic, hemiisotactic, syndiotactic, and stereoblock polymers can be produced by rational modification of the catalyst structure. Functional monomers are readily copolymerized with the less oxophilic late transition metal catalysts. Entirely new materials, not accessible with traditional Ziegler–Natta catalysts, have emerged, including high melting syndiotactic polystyrene and cycloaliphatic polymers. This article provides a broad overview of SSCs and their application in olefin polymerization. Evolution and classification of SSCs, polymerization of ethylene, propylene, as well as functional olefins, macromolecular architecture bearing polyolefin blocks are covered. Finally, heterogenization of SSCs for use in industrial processes is described.

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Single Site Catalysts and Cocatalysts

Malpass¹,

Band²

2012

Introduction to Industrial Polypropylene

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Metallocene Activation by Solid Acids

Cited by 22 publications

References 19 publications

Comparison of Support Effects on Phillips and Metallocene Catalysts

Comparison of Support Effects on Phillips and Metallocene Catalysts

Single‐Site Catalysts

Single Site Catalysts and Cocatalysts

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