Effect of silica-type sol–gel carrier’s structure and morphology on a supported Ziegler–Natta catalyst for ethylene polymerization

Korach, Łukasz; Czaja, Krystyna; Mrowiec-Białoń, Julita; Jarzębski, Andrzej B.

doi:10.1016/j.eurpolymj.2006.08.003

Cited by 6 publications

(6 citation statements)

References 16 publications

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“…They further made postulations from the SAXS results that ES40 xerogels appear to have a higher microstructural homogeneity indicating a thicker and stronger polymeric network which consisted of a highly condensed silica wall on one side with a thick polymeric chain barrier on the other, whereas the TEOS xerogels resulted in a lower homogeneity suggestive of a thinner polymeric chain wall. Further, ES40 xerogels exhibit larger pore size and micropore volume but lower surface area of silica xerogels than those observed in the corresponding TEOS sol-gel formulation2139.…”

Section: Discussionmentioning

confidence: 84%

Reversible Redox Effect on Gas Permeation of Cobalt Doped Ethoxy Polysiloxane (ES40) Membranes

Miller

Wang

Smart

et al. 2013

Sci Rep

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This work reports the remarkable effect of reversible gas molecular sieving for high temperature gas separation from cobalt doped ethoxy polysiloxane (CoES40) membranes. This effect stemmed from alternating the reducing and oxidising (redox) state of the cobalt particles embedded in the ES40 matrix. The reduced membranes gave the best H2 permeances of 1 × 10−6 mol m−2 s−1 Pa−1 and H2/N2 permselectivities of 65. The reduction process tailored a molecular gap attributed to changes in the specific volume between the reduced cobalt (Co(OH)2 and CoO) particles in the ES40 structure, thus allowing for the increased diffusion of gases. Upon re-oxidation, the tailored molecular gap became constricted as the particles reversed to Co3O4 resulting a lower gas diffusion, particularly for the larger gases ie. CO2 and N2. The ES40 matrix proved to be structurally rigid enough to withstand the reversible redox effect of cobalt particles across multiple cycles.

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Section: Discussionmentioning

confidence: 84%

Reversible Redox Effect on Gas Permeation of Cobalt Doped Ethoxy Polysiloxane (ES40) Membranes

Miller

Wang

Smart

et al. 2013

Sci Rep

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“…The obtained materials, prior to immobilization of the transition metal compound, were annealed at 200 o C and some samples were additionally modified with AlEt 2 Cl (i.e. catalyst sample B-Me/Al) as it was done during earlier investigations [4][5][6]. Supported catalyst for slurry polymerization were prepared by the impregnation of thermally pre-treated carrier with VOCI 3 in a hexane slurry at room temperature.…”

Section: Catalyst Preparationmentioning

confidence: 99%

“…In earlier investigations [4,5] we have found that the sol-gel method offered a high versatility and flexibility in production of potential carrier materials with a different structure and morphology. Besides immobilization of transition metal compound, such supported catalysts appeared to be active in low-pressure ethylene polymerization.…”

mentioning

confidence: 99%

“…Two-step modification of the support, including reaction with organoaluminum compound, clearly increases the activity as well as stability of the catalytic system. It was proposed then that the reason of favourable properties of such a catalyst was most likely a separation of the active species from the surface of a support with a "spacer" that was formed by the organoaluminum compound introduced in the modification step [4].…”

mentioning

confidence: 99%

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Copolymerization of ethylene with 1-hexene over vanadium catalysts immobilized on sol-gel silica

Białek

Korach²,

Czaja³

2007

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Silica-type materials with different structure and morphology, synthesized using sol-gel process, were applied as a carriers of organometallic catalytic systems (VOCl 3 /AlEt 2 Cl) for ethylene-1-hexene copolymerization. Carrier materials, prior to immobilization of the vanadium compound, were pre-treated using two modes: one-step thermal modification and two-steps modification including additional reaction with AlEt 2 Cl. It was found that the carrier's type and way of it's modification significantly influence the catalysts activity in ethylene-1-hexene copolymerization as well as the incorporation of higher 1-olefin. The favourable effect of two-step modification mode on the catalysts activity and 1-hexene incorporation efficiency was proposed.

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“…Copper-contained catalysts show a potential activity for the CO oxidation and have been extensively investigated during the past decades [16][17][18]. It is well known that SiO 2 is a good catalyst support and the performance of catalysts has a close relationship with the properties of supports [19][20][21][22][23]. Therefore, silica with hollow spherical structure was selected as supports of copper oxide (CuO) in present work, in order to study the influence of morphology of supports on catalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Preparation, Characterization and Catalytic Activity for CO Oxidation of SiO2 Hollow Spheres Supporting CuO Catalysts

et al. 2007

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Silica hollow spheres were synthesized by solgel process using carbon microspheres as templates, and used as supports for CuO/SiO 2 catalysts. The samples were characterized by TEM, nitrogen adsorption-desorption, XRD and TPR, and furthermore, the catalytic performance for CO oxidation was approached. The results indicated that the catalytic activity of CuO supported on SiO 2 hollow spheres exhibited much higher as compared to that supported on commercial SiO 2 . Enhancement of the catalytic activity may be attributed to the fact that the unique hollow spherical texture should facilitate the formation of main active species and gas diffusion in catalysts.

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Effect of silica-type sol–gel carrier’s structure and morphology on a supported Ziegler–Natta catalyst for ethylene polymerization

Cited by 6 publications

References 16 publications

Reversible Redox Effect on Gas Permeation of Cobalt Doped Ethoxy Polysiloxane (ES40) Membranes

Reversible Redox Effect on Gas Permeation of Cobalt Doped Ethoxy Polysiloxane (ES40) Membranes

Copolymerization of ethylene with 1-hexene over vanadium catalysts immobilized on sol-gel silica

Preparation, Characterization and Catalytic Activity for CO Oxidation of SiO2 Hollow Spheres Supporting CuO Catalysts

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