Review of Phillips Chromium Catalyst for Ethylene Polymerization

McDaniel, Max P.

doi:10.1002/9780470504437.ch10

Cited by 13 publications

(22 citation statements)

References 301 publications

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“…Over 80 million tons of PE are produced annually, a figure likely to rise [1]. Robert Banks and J. Paul Hogan at Phillips Petroleum found that chromium trioxide supported on silica (Cr/SiO 2 ) polymerizes ethylene [2], a few years prior to the discovery of Ziegler-Natta catalysts (TiCl x /MgCl 2 /AlR 3 ). Cr/SiO 2 , commonly referred to as Phillips catalyst, produces 40-50 % of high density PE globally [3].…”

Section: Introductionmentioning

confidence: 99%

Polymerization on CO-Reduced Phillips Catalyst initiates through the C–H bond Activation of Ethylene on Cr–O Sites

Delley¹,

Conley²,

Copéret³

2014

Catal Lett

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Investigation of the polymerization of ethylene on CO-reduced Phillips catalyst (1 wt% chromium) by infrared spectroscopy reveals the presence of new OH bands. In particular, an OH-band appears at 3,605 cm-1 , consistent with the interaction of the SiOH group with an adjacent Lewis acidic chromium center, Si-(l-OH)-Cr. Polymerization with d 4-ethylene leads to the formation of the isotopically shifted band at 2,580 cm-1 , consistent with heterolytic C-H activation of ethylene over a Cr-O bond to generate the first Cr-C bond in ethylene polymerization with Phillips catalyst, as recently observed on well-defined Cr(III) silicates.

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Section: Introductionmentioning

confidence: 99%

Polymerization on CO-Reduced Phillips Catalyst initiates through the C–H bond Activation of Ethylene on Cr–O Sites

Delley¹,

Conley²,

Copéret³

2014

Catal Lett

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“…However, both catalysts do polymerize ethylene to produce linear high molecular weight polymers, by a Cosseetype mechanism [2]. Both can also be supported on solid oxide carriers, with high porosity and sometimes high acidity [3,4]. In this paper we point out the often parallel, but also sometimes different, responses by the two catalysts to manipulation of those supports.…”

Section: Introductionmentioning

confidence: 87%

“…In its simplest form, the Phillips catalyst is made by depositing a chromium compound (usually trivalent) onto a support (usually silica) followed by calcination in dry oxygen. At about 400 • C, the chromium is oxidized into the hexavalent form, which spreads out and becomes anchored onto the support as chromate or dichromate surface esters [3,[5][6][7][8][9][10][11][12][13][14]. These species are then reduced by ethylene to a lower valence, expanding the potential coordination sphere, alkylating the Cr, and forming the coordinatively unsaturated active sites [3][4][5][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…At about 400 • C, the chromium is oxidized into the hexavalent form, which spreads out and becomes anchored onto the support as chromate or dichromate surface esters [3,[5][6][7][8][9][10][11][12][13][14]. These species are then reduced by ethylene to a lower valence, expanding the potential coordination sphere, alkylating the Cr, and forming the coordinatively unsaturated active sites [3][4][5][15][16][17][18][19][20]. Consequently, and somewhat unusually for inorganic industrial catalysts, the active sites are individually attached to the support.…”

Section: Introductionmentioning

confidence: 99%

“…The activity of Phillips catalyst is enhanced as the calcination temperature is increased above 400 • C, up to 900 • C. The surface becomes increasingly dehydroxylated, which removes ligands and probably introduces more strain into the anchoring bonds as the silica surface anneals [3,8,[21][22][23][24]. Due to this process, and because the surface is usually amorphous, variations appear in the reactivity of individual sites.…”

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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Olefin Polymers, Introduction

Kissin

2015

Kirk-Othmer Encyclopedia of Chemical Technology

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Polyolefin resins are a large family of semicrystalline and amorphous polymers and copolymers used as commodity plastics, engineering plastics, and elastomers. Industry produces a broad variety of polyolefin resins. They differ in chemical structure, molecular weight, stereoregularity, and the crystallinity degree. Polyolefin resins are manufactured by a number of technological processes. The latter include polymerization reactions with radical initiators in supercritical ethylene at 150–350°C and a variety of catalytic polymerization processes in hydrocarbon slurry, in a neat monomer, in solution, and in the gas phase. All the processes use three types of catalysts: Ziegler–Natta catalysts, chromium oxide catalysts, and metallocene catalysts. Polyolefin resins enjoy a large range of applications as commodity resins, such as engineering plastics, elastomers, synthetic rubbers, and specialty polymers. These applications include film, coatings, wire insulation, household and industrial containers, pipe and tubing of various types, and components of engineering articles. Because of their versatility, polyolefin resins have become the largest commercially manufactured polymer products in the world, ∼150 × 10 6 metric tons·yr −1 in 2013, which corresponds to over 50% of the total production of all plastic materials.

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Review of Phillips Chromium Catalyst for Ethylene Polymerization

Cited by 13 publications

References 301 publications

Polymerization on CO-Reduced Phillips Catalyst initiates through the C–H bond Activation of Ethylene on Cr–O Sites

Polymerization on CO-Reduced Phillips Catalyst initiates through the C–H bond Activation of Ethylene on Cr–O Sites

Comparison of Support Effects on Phillips and Metallocene Catalysts

Olefin Polymers, Introduction

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