Key Interactions in Heterogeneous Ziegler-Natta Catalytic Systems: Structure and Energetics of TiCl4-Lewis Base Complexes

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• 作者：Luigi Cavallo ; Silvia Del Piero ; Jean-Marie Ducé ; ré ; Rosalisa Fedele ; Andrea Melchior ; Giampiero Morini ; Fabrizio Piemontesi ; Marilena Tolazzi
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：March 22, 2007
• 年：2007
• 卷：111
• 期：11
• 页码：4412 - 4419
• 全文大小：156K
• 年卷期：v.111,no.11(March 22, 2007)
• ISSN：1932-7455

文摘

Extensive calorimetric investigations on the interaction of TiCl₄ with some Lewis bases are presented. Someof the bases were chosen for their industrial relevance in heterogeneous Ziegler-Natta polymerization ofpropene (ethyl benzoate, L2, diisobutyl phthalate, L3, (2R,3S)-diethyl 2,3-diisopropylsuccinate, L6, (2S,3S)-diethyl 2,3-diisopropylsuccinate, L7, and 9,9-bis(methoxymethyl)-9H-fluorene, L13) while other bases werechosen as probe molecules to explore the electronic and steric effects on the complexation energy (ethylacetate, L1, diethyl phthalate, L4, diethyl succinate, L5, tetrahydrofuran, L8, dimethoxyethane, L9,dimethoxypropane, L10, dimethoxybutane, L11, and 3,3-bis(methoxymethyl)-2,6-dimethylheptane, L12).1,1,2,2,-Tetrachloroethane was selected as the solvent for its low donating properties, which allows the focusto be on the metal-donor interaction. The calorimetric data are discussed and compared with the efficiencyof the derived catalysts. Further understanding is obtained by comparison of the experimental results withtheoretical calculations based on density functional theory (DFT). The performance of different computationalapproaches was validated by comparison of the calculated and experimental complexation energies.