オレフィンポリメリゼーション触媒における構造-活性関係:エントロピーは鍵ですか?
Gianluca Ciancaleoni1, Natascia Fraldi, Peter H M Budzelaar
1Dipartimento di Chimica, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
Journal of the American Chemical Society
|September 16, 2010
まとめ
特定の触媒を用いたプロペンのポリメリゼーションは,主にエントロピーによる遅い伝播率を示しています. この研究は,オレフィンポリメリゼーションのためのモノマー捕獲の間に触媒設計とエントロピー損失の管理の間の重要なリンクを明らかにしています.
科学分野:
- オーガノメタリック化学
- ポリマー科学は,ポリマー科学である.
- 計算化学はコンピュータ化学である.
背景:
- ビス ((フェノキシアミン) ジルコニウム触媒は,オレフィンポリメリゼーションに使用されます.
- メチルアルミノキサン (MAO) は,一般的な共触媒である.
研究 の 目的:
- MAOを含むbis(フェノキシアミン) Zr-ディベンジル触媒を使用してプロペンのポリメリゼーションの活性化パラメータを調査する.
- このシステムにおける連鎖伝播速度を制限する要因を決定する.
- モノマー捕獲時の触媒の行動とエントロピーの損失の関係を探求する.
主な方法:
- アクティベーションパラメータの実験的測定.
- 密度関数理論 (DFT) による計算.
- オレフィンポリメリゼーション触媒の文献レビュー.
主要な成果:
- 実験およびDFTの計算では,低鎖の伝播率の主な寄与者として,エントロピック項を一貫して特定しました.
- 伝播速度と,モノマー捕獲時にエントロピーの損失を軽減する触媒の能力の間の強い相関が提案されました.
結論:
- モノマー捕獲に関連したエントロピックペナルティは,この触媒系におけるチェーン伝播速度に大きな影響を及ぼします.
- エントロピー管理を理解することは,効率的なオレフィンポリメリゼーション触媒の設計に不可欠です.
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