New aspects of the induction period of ethene polymerization using Phillips CrOx/SiO2 catalyst probed by XPS, TPD and EPMA

Liu, Boping; Nakatani, Hisayuki; Terano, Minoru

doi:10.1016/s1381-1169(02)00019-5

Cited by 78 publications

(59 citation statements)

References 54 publications

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“…The growth of polyethylene seems to be associated with the presence of bivalent chromium compounds at the model catalyst surface. These findings agree with the previously proposed mechanisms [1,[31][32][33][34]. Moreover, it is known that aldehyde could by formed during ethylene polymeration [1].…”

Section: Mechanism Of Ethylene Polymerizationsupporting

confidence: 92%

Activation processes and polyethylene formation on a phillips model catalyst studied by laser ablation, laser desorption, and static secondary ion mass spectrometry

Aubriet

Müller²,

Poleunis

et al. 2006

J. Am. Soc. Mass Spectrom.

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Since the discovery of the Phillips catalysts, there still is much uncertainty concerning their activation, their molecular structure, the nature of the active chromium sites, and the polymerization mechanisms. Surface techniques are not easy to be used for such study according to the nonconductive behavior of the support. Therefore, model Phillips catalyst is elaborated by spin coating a trivalent chromium precursor on a silicon wafer. The surface characterization of this model catalyst is conducted by laser ablation mass spectrometry (LA-MS), laser desorption/ionization mass spectrometry (LDI-MS), and static secondary ion mass spectrometry (s-SIMS), at different steps of its preparation. To validate our approach, a comparison is also made between the model and the real Philips catalyst. Moreover, the model catalyst efficiency for polyethylene synthesis is evaluated and allows us to discuss the validity of the mechanisms previously proposed to explain the catalytic process. The characterization of Phillips model catalyst by mass spectrometry allows us to better understand the activation processes of such catalyst. Depending on the activation temperature, chromium oxide species are formed and anchored at the support surface. They consist mainly in mono-chromium sites at high temperature. The chromium valence is hexavalent. This model catalyst is active for the polymerization of ethylene. A pseudo-oligomer molecular weight distribution is observed by LA-MS, whereas s-SIMS allows us to elucidate the anchorage of the polymer at activate chromium surface sites. (J Am Soc Mass Spectrom 2006, 17, 406 -414)

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Section: Mechanism Of Ethylene Polymerizationsupporting

confidence: 92%

Activation processes and polyethylene formation on a phillips model catalyst studied by laser ablation, laser desorption, and static secondary ion mass spectrometry

Aubriet

Müller²,

Poleunis

et al. 2006

J. Am. Soc. Mass Spectrom.

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“…4c and d, respectively), the peak observed at around 576.6 eV corresponds to the characteristic binding energy of Cr 3+ species. [54][55][56] Aer adsorption, this peak shied in Cr2p spectra, and binding energy peaks of both LSB750 (Fig. 4c) and LSB900 (Fig.…”

Section: Possible Adsorption Mechanismsmentioning

confidence: 94%

Superb adsorption capacity of biochar derived from leather shavings for Congo red

Huang

Peng

et al. 2018

RSC Adv.

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“…[6] These Phillipstype catalysts comprise a range of different active species, the exact nature of which is still not fully resolved. [7] Summary: The effective immobilization and activation of a single-site chromium catalyst for ethylene polymerization has been achieved using MgCl 2 /AlR n (OEt) 3 À n supports, without the use of methylaluminoxane (MAO) or a borate activator. High catalyst activity and a spherical polyethyleneparticle morphology is obtained.…”

Section: Introductionmentioning

confidence: 99%

Immobilization and Activation of a Single‐Site Chromium Catalyst for Ethylene Polymerization using MgCl₂/AlR_n(OEt)_3 − n Supports

Severn

Kukalyekar

Rastogi

et al. 2005

Macromol. Rapid Commun.

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Summary: The effective immobilization and activation of a single‐site chromium catalyst for ethylene polymerization has been achieved using MgCl2/AlRn(OEt)3 − n supports, without the use of methylaluminoxane (MAO) or a borate activator. High catalyst activity and a spherical polyethylene‐particle morphology is obtained. Furthermore, the single‐site characteristics of the catalyst are retained, the narrow molecular weight distribution of the polymers obtained are apparent from gel permeation chromatography (GPC) and confirmed by rheological characterization.Shear frequency dependence of the storage modulus of (♦ and ▴) polyethylene ($\overline M _{\rm w} /\overline M _{\rm n}$ = 1.8–1.9) prepared using an immobilized Cr catalyst, compared to (▪) a reference polymer having $\overline M _{\rm w} /\overline M _{\rm n}$ = 4.1.imageShear frequency dependence of the storage modulus of (♦ and ▴) polyethylene ($\overline M _{\rm w} /\overline M _{\rm n}$ = 1.8–1.9) prepared using an immobilized Cr catalyst, compared to (▪) a reference polymer having $\overline M _{\rm w} /\overline M _{\rm n}$ = 4.1.

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New aspects of the induction period of ethene polymerization using Phillips CrOx/SiO2 catalyst probed by XPS, TPD and EPMA

Cited by 78 publications

References 54 publications

Activation processes and polyethylene formation on a phillips model catalyst studied by laser ablation, laser desorption, and static secondary ion mass spectrometry

Activation processes and polyethylene formation on a phillips model catalyst studied by laser ablation, laser desorption, and static secondary ion mass spectrometry

Superb adsorption capacity of biochar derived from leather shavings for Congo red

Immobilization and Activation of a Single‐Site Chromium Catalyst for Ethylene Polymerization using MgCl₂/AlR_n(OEt)_3 − n Supports

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New aspects of the induction period of ethene polymerization using Phillips CrOx/SiO2 catalyst probed by XPS, TPD and EPMA

Cited by 78 publications

References 54 publications

Activation processes and polyethylene formation on a phillips model catalyst studied by laser ablation, laser desorption, and static secondary ion mass spectrometry

Activation processes and polyethylene formation on a phillips model catalyst studied by laser ablation, laser desorption, and static secondary ion mass spectrometry

Superb adsorption capacity of biochar derived from leather shavings for Congo red

Immobilization and Activation of a Single‐Site Chromium Catalyst for Ethylene Polymerization using MgCl2/AlRn(OEt)3 − n Supports

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Immobilization and Activation of a Single‐Site Chromium Catalyst for Ethylene Polymerization using MgCl₂/AlR_n(OEt)_3 − n Supports