イソブテンのポリメリゼーションは,ケラートするディボラン共同イニシアターを使用して行われます.
Stewart P Lewis1, Nicholas J Taylor, Warren E Piers
1Department of Polymer Science, University of Akron, Akron, OH 44325-3909, USA.
Journal of the American Chemical Society
|December 4, 2003
まとめ
ルイス酸ディボランは,イソブテンポリメリゼーションに有効です. アルキル塩化物やエーテルと安定したイオンペアを形成し,高温でさらに反応することができる.
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
背景:
- ルイス酸ディボランは,イソブテンポリメリゼーションの強力なイニシアターです.
- ディボランと電離性の種との反応機構を理解することは,ポリメリゼーションを制御するために非常に重要です.
研究 の 目的:
- ルイス酸ディボランとクミル塩化物およびクミルメチルエーテルとの反応経路を調査する.
- これらの反応で形成される中間種を,先端のスペクトロスコーピテクニックを用いて特徴づける.
主な方法:
- 温度変数1Hと19Fの核磁気共振 (NMR) スペクトロスコピーを用いた.
- 特定のイオンペアの構造を決定するために,X線結晶学を用いた.
主要な成果:
- 安定したイオンペア (2a,2b) は,低温でディボランと電性反応剤の間に形成されます.
- 高温では,これらのイオンペアがサイクリングされ,フェニル-1,3,3-トリメチルインダン (3) またはアニオン分解を形成します.
- Ph3C-Clとの反応により,弱く関連したmu-Cl対離子素を持つユニークなイオンペア (4) が生成された.
結論:
- ディボランのルイス酸性は,反応性イオンペアの形成を促進します.
- 観察された反応は,カチオンのポリメリゼーションの開始にディボランが関与する複雑なメカニズム的経路を強調しています.
関連する概念動画
01:20Anionic Chain-Growth Polymerization: Overview
The polymerization process that involves carbanion as an intermediate is called anionic polymerization. It is also a type of addition or chain-growth polymerization. Anionic polymerization gets initiated by a strong nucleophile such as an organolithium or a Grignard reagent. The most commonly used initiator for anionic polymerization is butyl lithium. Monomers involved in anionic polymerization must possess a vinyl group bonded to one or two electron-withdrawing groups. For instance,...
01:04Anionic Chain-Growth Polymerization: Mechanism
The mechanism for anionic chain-growth polymerization involves initiation, propagation, and termination steps. In the initiation step, a nucleophilic anion, such as butyl lithium, initiates the polymerization process by attacking the π bond of the vinylic monomer. As a result, a carbanion, stabilized by the electron‐withdrawing group, is generated. The resulting carbanion acts as a Michael donor in the propagation step and attacks the second vinylic monomer, which acts as a Michael acceptor.
00:57Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...
01:13Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...