Effect of EtOH/MgCl2 Molar Ratios on the Catalytic Properties of MgCl2-SiO2/TiCl4 Ziegler-Natta Catalyst for Ethylene Polymerization
| Autor: | Supanan Patthamasang, Bunjerd Jongsomjit, Piyasan Praserthdam |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
polyethylene
Ziegler-Natta catalyst Magnesium Chloride spherical support Pharmaceutical Science chemistry.chemical_element Article Catalysis Polymerization Analytical Chemistry Adduct lcsh:QD241-441 chemistry.chemical_compound lcsh:Organic chemistry MgCl2 morphology Drug Discovery Polymer chemistry Physical and Theoretical Chemistry Ziegler–Natta catalyst Titanium Heptane Ethanol Chemistry Magnesium Organic Chemistry Ethylenes Polyethylene Silicon Dioxide silica Chemistry (miscellaneous) Molecular Medicine ethanol |
| Zdroj: | Molecules Volume 16 Issue 10 Pages: 8332-8342 Molecules, Vol 16, Iss 10, Pp 8332-8342 (2011) |
| ISSN: | 1420-3049 |
| DOI: | 10.3390/molecules16108332 |
| Popis: | MgCl(2)-SiO(2)/TiCl(4) Ziegler-Natta catalysts for ethylene polymerization were prepared by impregnation of MgCl(2) on SiO(2) in heptane and further treatment with TiCl(4). MgCl(2)·nEtOH adduct solutions were prepared with various EtOH/MgCl(2) molar ratios for preparation of the MgCl(2)-supported and MgCl(2)-SiO(2)-supported catalysts in order to investigate the effect on polymerization performance of both catalyst systems. The catalytic activities for ethylene polymerization decreased markedly with increased molar ratios of [EtOH]/[MgCl(2)] for the MgCl(2)-supported catalysts, while for the bi-supported catalysts, the activities only decreased slightly. The MgCl(2)-SiO(2)-supported catalyst had relatively constant activity, independent of the [EtOH]/[MgCl(2)] ratio. The lower [EtOH]/[MgCl(2)] in MgCl(2)-supported catalyst exhibited better catalytic activity. However, for the MgCl(2)-SiO(2)-supported catalyst, MgCl(2) can agglomerate on the SiO(2) surface at low [EtOH]/[MgCl(2)] thus not being not suitable for TiCl(4) loading. It was found that the optimized [EtOH]/[MgCl(2)] value for preparation of bi-supported catalysts having high activity and good spherical morphology with little agglomerated MgCl(2) was 7. Morphological studies indicated that MgCl(2)-SiO(2)-supported catalysts have good morphology with spherical shapes that retain the morphology of SiO(2). The BET measurement revealed that pore size is the key parameter dictating polymerization activity. The TGA profiles of the bi-supported catalyst also confirmed that it was more stable than the mono-supported catalyst, especially in the ethanol removal region. |
| Databáze: | OpenAIRE |
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