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Ethylene tetramerization catalyst using the cationic chromium complex
- Alternative Title
- Eun Ho Kim
- Author(s)
- 김은호
- Alternative Author(s)
- Eun Ho Kim
- Advisor
- 이분열
- Department
- 일반대학원 분자과학기술학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2017-02
- Language
- eng
- Alternative Abstract
- Ethylene tetramerization catalyst composed of PNP ligand, Cr(III) complex, and MAO is useful in the production of 1-octene, in which a concern is the use of expensive MAO in excess. Herein, we report a catalytic system that avoids the use of MAO. Metathesis of CrCl3(THF)3 and [(CH3CN)4Ag]+[B(C6F5)4]- afforded [L4CrIIICl2]+[B(C6F5)4]- (L = CH3CN or THF), which was converted to [(PNP)CrCl2L2]+[B(C6F5)4]- where PNP is iPrN(PPh2)2 (1) or [CH3(CH2)16]2CHN(PPh2)2 (2). The molecular structures of [(THF)4CrIIICl2]+[B(C6F5)4]- and [1-CrCl2(THF)2]+[B(C6F5)4]- were unambiguously determined by X-ray crystallography. The cationic (PNP)CrIII complexes paired with [B(C6F5)4]- anion, i.e., [(PNP)CrCl2(CH3CN)2]+[B(C6F5)4]- exhibit high activity in chlorobenzene when activated with common trialkylaluminum (Me3Al, Et3Al, and iBu3Al). The activity and selectivity were comparable to those of the original MAO-based Sasol system (1-CrCl3/MMAO). The Cr complex [2-CrCl2(CH3CN)2]+[B(C6F5)4]- bearing long alkyl chains activated with Et3Al or iBu3Al showed high activity in more desirable methylcyclohexane solvent (89 Kg/g-Cr/h) and much higher activity in cyclohexene bearing -electrons (168 Kg/g-Cr/h). Negligible catalyst deactivation, formation of negligible amount of PE (0.3%), and formation of less amount of unwanted side products above C10 are another advantages gained by the catalytic system [2-CrCl2(CH3CN)2]+[B(C6F5)4]-/Et3Al in cyclohexene. [B(C6F5)4]- anion is compatible with trialkylaluminum in itself once it is not paired with trityl cation, and, hence, [(PNP)CrCl2(CH3CN)2]+[B(C6F5)4]-/Et3Al exhibited high activity in contrast with very low activity of the reported system composed of [Ph3C]+[B(C6F5)4]-, i.e., 1/CrCl3(THF)3/[Ph3C]+[B(C6F5)4]-/Et3Al.
- Fulltext
- Appears in Collections:
- Graduate School of Ajou University > Department of Molecular Science and Technology > 3. Theses(Master)
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