ポリメリゼーションの方法としてのニッケル触媒アルケンの機能不全
Julia N Katzbaer1, Vincent M Torres1, Elizabeth Elacqua1
1Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
Journal of the American Chemical Society
|June 21, 2023
まとめ
この研究では,ポリマー合成のための新しいニッケル触媒アルケンの二機能化が導入され,規則的なアリル群間隔と高い熱安定性を持つユニークなポリ[アリレン-α-α-アリル]エチレンが生成されます.
科学分野:
- ポリマー化学
- 有機合成
- 材料科学
背景:
- アルケンの二機能化は複雑な分子を作るための重要な合成ツールです.
- ポリマー合成,特にステレオ定義ポリマーにおけるその応用は未探究のままである.
- 新しいポリメリゼーションの方法の開発は,先進的な材料にとって極めて重要です.
研究 の 目的:
- ポリマー合成のためのニッケル触媒アルケンの二機能化の最初の例を報告する.
- 結果となるポリマーの地域選択性と特性を調査する.
- 新型ポリアリレン-α-エチレンを作るためのこの方法の可能性を調査する.
主な方法:
- アリルボロンエステルとアリルブロミドを用いたアルケンのニッケル触媒二機能化.
- アルケーン全体に特異的な添加を伴う地域選択的ポリメリゼーション.
- オリゴメア種からポリマーを分離するための分化.
- ポリマーの性質を決定するための熱分析 (TGA,DSC)
主要な成果:
- 新しい Ni-触媒による二機能化ポリメリゼーションによるポリ[アリレン-α-(アリル) エチレンの合成に成功した.
- 末端炭素にアリルブロミドと,内部ベンジル炭素にアリルボロンエステルを地域選択的に加える.
- 分子重量30~175kDaのポリマーを得ている.
- ポリマーは高熱安定性 (~399 °C) と90 °Cのガラス化温度 (Tg) を表しています.
結論:
- この研究は,アルケンの二機能化により,ポリ[アリレン-α-アリル]エチレンを合成するための新しい経路を確立している.
- その結果生成されるポリマーは,ポリチレンなどの既定のポリマーと比べて望ましい熱特性を持っています.
- この方法により 設計上の特性を有する 高度なポリマーが作れるのです
さらに関連する動画
関連する概念動画
02:35Free-Radical Chain Reaction and Polymerization of Alkenes
8.0K
The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a repeating unit, while the terminal groups are considered insignificant. The average degree of polymerization represents the number of repeating units in the polymer molecule and is denoted by the subscript n.
8.0K
01:13Olefin Metathesis Polymerization: Overview
2.2K
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...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
2.2K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
7.8K
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
7.8K
01:17Ziegler–Natta Chain-Growth Polymerization: Overview
3.4K
Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta...
3.4K
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
2.0K
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
2.0K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.4K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.4K