尿素アニオン:リング開きポリメリゼーションのためのシンプル,高速,選択的触媒
Binhong Lin1, Robert M Waymouth1
1Department of Chemistry, Stanford University , Stanford, California 94305, United States.
Journal of the American Chemical Society
|January 21, 2017
まとめ
新しい尿素ベースの触媒は,様々なサイクルモノメアの迅速で選択的なリング開きポリメリゼーション (ROP) を可能にします. これらの効率的な触媒は 室温で素早く 高品質の生物分解性ポリマーを生成します
科学分野:
- ポリマー化学
- 材料科学
背景:
- アリファティックポリエステルとポリカーボネートは 価値ある生物再生可能,生物適合性,生物分解性材料です.
- 環開きポリメリゼーション (ROP) は,これらのポリマーをサイクルモノマーから合成するための重要な方法である.
研究 の 目的:
- 循環性モノメアのリング開封ポリメリゼーション (ROP) のための新しい効率的な触媒を開発する.
- ROPにおける脱プロトン化尿素の触媒活性と選択性を調査する.
主な方法:
- アニオン触媒を生成するダイアリル尿素の脱プロトン化.
- 乳酸,バレロラクトン,カプロラクトン,サイクル炭酸,サイクルフォスフォースターのリング開封ポリメリゼーション (ROP)
- ポリマーの分子量分布 (Đ) と反応運動の分析
主要な成果:
- ROPの迅速で選択的な触媒として機能する.
- 触媒の反応性は,アリル環の電子取り除く置換物と相関する.
- 室温で数秒 (1~12秒) のうちに高い変換率 (∼90%) を達成する.
- 狭い分子量分布 (Đ = 1.06 から 1.14) を有するポリマーが生成された.
結論:
- ダイアリル尿素アニオンは,生きている ROP のための多用途な触媒です.
- アリル置換剤を改変することによって,触媒の活性を調節することができます.
- これらの触媒は,生物分解性ポリマーを合成するための迅速で効率的で調整可能な方法を提供します.
さらに関連する動画
関連する概念動画
Anionic Chain-Growth Polymerization: Overview
2.7K
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,...
2.7K
Preparation of 1° Amines: Azide Synthesis
4.8K
Direct alkylation of ammonia produces polyalkylated amines, along with a quaternary ammonium salt. To exclusively prepare primary amines, the azide synthesis method can be used.
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
4.8K
Cationic Chain-Growth Polymerization: Mechanism
3.0K
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...
3.0K
Olefin Metathesis Polymerization: Overview
2.7K
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...
2.7K
Base-Catalyzed Ring-Opening of Epoxides
10.8K
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
10.8K
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
3.3K
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
3.3K


