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Preparation of Epoxides03:00

Preparation of Epoxides

9.8K
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
9.8K
Acid-Catalyzed Ring-Opening of Epoxides02:24

Acid-Catalyzed Ring-Opening of Epoxides

9.7K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
9.7K
Base-Catalyzed Ring-Opening of Epoxides02:26

Base-Catalyzed Ring-Opening of Epoxides

11.0K
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...
11.0K
Olefin Metathesis Polymerization: Overview01:13

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...
2.7K
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)01:16

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
Sharpless Epoxidation02:57

Sharpless Epoxidation

5.4K
The conversion of allylic alcohols into epoxides using the chiral catalyst was discovered by K. Barry Sharpless and is known as Sharpless epoxidation. The use of a chiral catalyst enables the formation of one enantiomer of the product in excess. This chiral catalyst is mainly a chiral complex of titanium tetraisopropoxide and tartrate ester (specific stereoisomer). The stereoisomer used in the chiral catalyst dictates the formation of the enantiomer of the product. In other words, the use of...
5.4K
  1. ホーム
  2. エポキシド,ラクトン,アンヒドリド,二酸化炭素の混合物からの化学選択ポリメリゼーション
  1. ホーム
  2. エポキシド,ラクトン,アンヒドリド,二酸化炭素の混合物からの化学選択ポリメリゼーション

関連する実験動画

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
07:36

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Published on: November 9, 2019

8.5K

エポキシド,ラクトン,アンヒドリド,二酸化炭素の混合物からの化学選択ポリメリゼーション

Charles Romain1, Yunqing Zhu1, Paul Dingwall1

  • 1Department of Chemistry, Imperial College London , London SW7 2AZ, U.K.

Journal of the American Chemical Society
|March 23, 2016

PubMed で要約を見る

まとめ
この要約は機械生成です。

新しいジンク触媒は,異なるポリメリゼーションタイプを切り替えることで,ポリマー組成を正確に制御できます. この突破により,設計されたブロック配列と予測可能なエステルと炭酸塩構造を持つポリマーが作られます.

さらに関連する動画

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications
09:22

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Published on: August 28, 2015

19.8K
Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
05:48

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Published on: November 21, 2017

8.7K

関連する実験動画

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
07:36

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Published on: November 9, 2019

8.5K
Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications
09:22

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Published on: August 28, 2015

19.8K
Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
05:48

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Published on: November 21, 2017

8.7K

科学分野:

  • ポリマー化学
  • カタリシス
  • 材料科学

背景:

  • モノマー混合物のポリマー組成を制御することは,ポリマー科学における重要な課題です.
  • 既存の方法では シーケンスや組成を正確に 決定する能力が欠けています

研究 の 目的:

  • リング開きポリメリゼーション (ROP) とリング開き共ポリメリゼーション (ROCOP) の両方に単一の切り替え可能な触媒を調査する.
  • ポリマーブロックの配列と予測可能な組成を単一の触媒システムで制御する.

主な方法:

  • ディジンク触媒の研究に実験的・理論的手法を使用した.
  • 4つのモデルモノメアの共ポリマー化: ε-カプロラクトン,サイクロヘクセン酸化物,フタルアンヒドリド,二酸化炭素を調査した.
  • モノメアの選択性と触媒の切り替え動作を分析した.

主要な成果:

  • ディジンク触媒は,異なるモノマーに対して高い選択性を示し,異なるポリメリゼーションサイクルを可能にしました.
  • ポリマーにおけるブロック配列形成の精密な制御を達成した.
  • 予測可能なエステルと炭酸化合物を 合成した

結論:

  • 単一の触媒は,連続的ポリメリゼーションのための正対単体反応性を効果的に制御できます.
  • 金属鎖の末端群の相互作用を理解することは,ポリマーブロック配列の設計の鍵です.
  • このアプローチは,特異な性質を持つ複雑なポリマーアーキテクチャを設計するための新しい経路を提供します.