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Facile Investigation of Ti3+ State in Ti-based Ziegler-Natta Catalyst with A Combination of Cocatalysts Using Electron Spin Resonance (ESR)
- Source :
- Bulletin of Chemical Reaction Engineering & Catalysis, Vol 15, Iss 1, Pp 55-65 (2020)
- Publication Year :
- 2019
- Publisher :
- Bulletin of Chemical Reaction Engineering and Catalysis, 2019.
-
Abstract
- This study aims to investigate the influences of a combination of cocatalysts including triethylaluminum (TEA) and tri-n-octylaluminum (TnOA) for activation of a commercial Ti-based Ziegler-Natta catalyst during ethylene polymerization and ethylene/1-hexene copolymerization on the change in Ti3+ during polymerization. Thus, electron spin resonance (ESR) technique was performed to monitor the change in Ti3+ depending on the catalyst activation by a single and combination of cocatalyst. It revealed that the amount of Ti3+ played a crucial role on both ethylene polymerization and ethylene/1-hexene copolymerization. For ethylene polymerization, the activation with TEA apparently resulted in the highest catalytic activity. The activation with TEA+TnOA combination exhibited a moderate activity, whereas TnOA activation gave the lowest activity. In case of ethylene/1-hexene copolymerization, it revealed that the presence of 1-hexene decreased activity. The effect of different cocatalysts tended to be similar to the one in the absence of 1-hexene. The decrease of temperature from 80 to 70 °C in ethylene/1-hexene copolymerization tended to lower catalytic activity for TnOA and TEA+TnOA, whereas only slight effect was observed for TEA system. The effect of different cocatalyst activation on the change of Ti3+ state of catalyst was elucidated by ESR measurement. It appeared that the activation of catalyst with TEA+TnOA combination essentially inhibited the reduction of Ti3+ to Ti2+ leading to lower activity. Furthermore, the polymer properties such as morphology and crystallinity can be altered by different cocatalysts. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
- Subjects :
- Ethylene
02 engineering and technology
01 natural sciences
cocatalysts
Catalysis
law.invention
Crystallinity
chemistry.chemical_compound
ziegler-natta catalyst
Chemical engineering
law
Copolymer
Ziegler–Natta catalyst
Electron paramagnetic resonance
chemistry.chemical_classification
010405 organic chemistry
Process Chemistry and Technology
electron spin resonance
Polymer
021001 nanoscience & nanotechnology
ethylene polymerization
0104 chemical sciences
Polymerization
chemistry
titanium oxidation state
TP155-156
0210 nano-technology
Nuclear chemistry
Subjects
Details
- ISSN :
- 19782993
- Volume :
- 15
- Database :
- OpenAIRE
- Journal :
- Bulletin of Chemical Reaction Engineering & Catalysis
- Accession number :
- edsair.doi.dedup.....65cbef401e8af6a7eb9d2743f820d775