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Titanium-based phenoxy-imine catalyst for selective ethylene trimerization: effect of temperature on the activity, selectivity and properties of polymeric side products

Titanium-based phenoxy-imine catalyst for selective ethylene trimerization: effect of temperature on the activity, selectivity and properties of polymeric side products

Authors :
Lionel Magna
Typhène Michel
Helene Olivier-Bourbigou
Astrid Cordier
Pierre-Alain Breuil
Jean Raynaud
Christophe Boisson
Vincent Monteil
Université Claude Bernard Lyon 1 (UCBL)
Université de Lyon
IFP Energies nouvelles (IFPEN)
Source :
Catalysis Science & Technology, Catalysis Science & Technology, Royal Society of Chemistry, 2020, 10 (6), pp.1602-1608. ⟨10.1039/C9CY02056J⟩
Publication Year :
2020
Publisher :
HAL CCSD, 2020.

Abstract

International audience; The reactivity of a phenoxy-imine-ether system (FI)TiCl3/MAO was studied toward selective ethylene trimerization. This system was shown to either trimerize or polymerize ethylene depending on the reaction temperature. Its selectivity switches from a significant production of the trimerization product, 1-hexene (85 wt %, 520-450 kg1-hexene gTi-1 h-1) between 30 and 40 °C, to a moderate polyethylene formation (70-80 wt %, 60-70 kgpolyethylene gTi-1 h-1) at higher reaction temperature (T > 60 °C). Polymerization was investigated based on an original "polymer-to-catalyst" strategy aiming at identifying the active species responsible for this side reaction. Using DSC, SEC and high temperature 13 C NMR analyses, polyethylenes were found to exhibit high molar masses (> 10 5 g mol-1) and a low 1-hexene content (< 1 mol %) at any temperature. Kinetic studies support that trimerization and polymerization species are generated from the catalyst precursor at 40 °C but a parallel process may occur at higher temperature. The increase dispersity to 4.6 at 80 °C suggests a change from single to multisite catalysis. The poor comonomer incorporation ability of the active species is reminiscent of a molecular Ziegler Natta or a bulky postmetallocene catalyst.

Details

Language :
English
ISSN :
20444753
Database :
OpenAIRE
Journal :
Catalysis Science & Technology, Catalysis Science & Technology, Royal Society of Chemistry, 2020, 10 (6), pp.1602-1608. ⟨10.1039/C9CY02056J⟩
Accession number :
edsair.doi.dedup.....453a161e9c73d6cada9e61c1f4f9a42d
Full Text :
https://doi.org/10.1039/C9CY02056J⟩