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グループ4 八面体ベンザミジナート複合体:圧力調節プロピレンのポリメリゼーションにおける合成,構造,および触媒的活動
Victoria Volkis1, Elza Nelkenbaum, Anatoli Lisovskii
1Department of Chemistry, Institute of Catalysis Science and Technology, Technion, Israel Institute of Technology, Haifa 32000, Israel.
Journal of the American Chemical Society
|February 20, 2003
まとめ
グループ4の金属のベンザミジナート複合体はプロピレンポリメリゼーションを触媒化し,圧力がポリマーの戦術性をアタクティックからアイソタクティックに制御します. 触媒の構造と共触媒は,活性とステレオ規則性に大きな影響を与える.
科学分野:
- 有機金属化学 有機金属化学
- ポリマー化学のポリマー化学について
- カタリシス カタリシス カタリシス
背景:
- ベンザミジナートリガンドは,金属複合体の合成のために調整可能なステリックおよび電子特性を提供します.
- グループ4の金属複合体は,オレフィンポリメリゼーションの触媒として広く研究されています.
研究 の 目的:
- ベンザミジナートリガンドとグループ4の金属複合体を合成し,特徴づけること.
- プロピレンポリメリゼーションにおけるこれらの複合体の触媒活性を調べる.
- 反応条件と複雑な構造がポリマー微細構造にどのように影響するかを理解する.
主な方法:
- ベンザミジナート複合物の合成とX線 difrractionの研究.
- プロピレンポリメリゼーションの実験では,MAOまたはB ((C ((6) F ((5)) (((3) コカタリストを使用した.
- 反応パラメータの関数として,ポリマーマイクロ構造 (戦術性,ステレオ規則性) の分析.
主要な成果:
- ZrとTiの八面体ベンザミジナート複合体を合成した.
- 触媒の活性とステレオレギュラリティは,圧力,溶媒,共触媒によって調節された.
- 複合体9でB (C) (6) F (5)) (3) は,高同位性ポリプロピレン (98% mmmm) を生成した.
- コンプレックス10は高圧で弾性ポリプロピレンを生産した.
- エラストメアは,エピメリゼーションによる交互に異質的領域とステレオデフェクトを交互に示した.
結論:
- ベンザミジナート複合体は,ステレオレギュラープロピレンポリメリゼーションの汎用な触媒である.
- 圧力は,ポリマーの戦術性を制御するための重要なパラメータです.
- 複雑な構造とコカタリストの選択は,望ましいポリマー特性の達成に不可欠です.
関連する概念動画
Carboxylic Acid Derivatives: Overview
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Structures of Carboxylic Acid Derivatives
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Preparation of Acid Anhydrides
One of the methods for preparing symmetrical or unsymmetrical acid anhydrides involves the treatment of acid chlorides with the sodium salt of carboxylic acids. The reaction proceeds via a nucleophilic acyl substitution.
The carboxylate ion acts as a nucleophile that attacks the carbonyl carbon of the acid chloride to form a tetrahedral intermediate. Subsequently, the re-formation of the carbonyl group with the loss of the chloride ion as a leaving group leads to the formation of an acid...
The carboxylate ion acts as a nucleophile that attacks the carbonyl carbon of the acid chloride to form a tetrahedral intermediate. Subsequently, the re-formation of the carbonyl group with the loss of the chloride ion as a leaving group leads to the formation of an acid...
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Polymer Classification: Architecture
Polymers are classified as linear or branched on the basis of their chain architecture. The polymer chains in linear polymers have a long chain-like structure with minimal to no branching at all. Even if a polymer features large substituent groups on the monomer, which appear as branches to the skeleton, it is not considered a branched polymer. A branched polymer contains secondary polymer chains that arise from the main polymer chain. The branching occurs when the polymer growth shifts from...
Polymer Classification: Stereospecificity
Polymerization generates chiral centers along the entire backbone of a polymer chain. Accordingly, the stereochemistry of the substituent group has a significant effect on polymer properties. Polymers formed from monosubstituted alkene monomers feature chiral carbons at every alternate position in the polymer backbone. Relative to the predominant orientation of substituents at the adjacent chiral carbons, the polymer can exist in three different configurations: isotactic, syndiotactic, and...

