パラジアム触媒によるエテンのアクロレイン・ジメチルアセタールとの共ポリメリゼーション:触媒作用と非活性化
Weidong Li1, Xiaochun Zhang, Auke Meetsma
1Dutch Polymer Institute/Center for Catalytic Olefin Polymerization, Stratingh Institute for Chemistry and Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Journal of the American Chemical Society
|September 30, 2004
まとめ
エテンをアクロレインジメチルアセタールと共聚合すると,枝分かれしたポリマーが得られます. カチオンパラジウム触媒システムにメタノールを添加すると,無効化を阻害し,このポリメリゼーションプロセスの生産性を高めます.
科学分野:
- ポリマー化学のポリマー化学について
- 有機金属化学 有機金属化学
背景:
- カチオンのアルファ-ダイミンパラジウム触媒は,エテンの共ポリメリゼーションを可能にします.
- アクロレインジメチルアセタール (ADMA) は,枝分かれしたポリマーアーキテクチャを作成するための機能的なモノマーです.
研究 の 目的:
- パラジウム触媒を用いて,エチンのADMAとの共聚合を調査する.
- ポリメリゼーションの効率を高めるために,触媒の非活性化経路を特定し,軽減します.
主な方法:
- エテナとADMAの共ポリメリゼーション.
- カチオン性アルファ-ダイミンパラジウムケラート触媒を用いて.
- 監視触媒の無効化メカニズム.
主要な成果:
- 枝分かれコポリマーが成功して合成されました.
- 触媒の無効化はメタノールの除去として識別され,惰性パラジウム種を形成しました.
- 反応混合物へのメタノール添加により,活性化が著しく遅れた.
結論:
- メタノール添加は,エテナ-ADMA共ポリメリゼーションにおける触媒の寿命と生産性を向上させるための効果的な戦略です.
- 不活性化経路を理解することで,パラジウム触媒によるオレフィンポリメリゼーションのプロセスの最適化が可能になります.
さらに関連する動画
関連する概念動画
02:50Catalysis
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
02:45Acid-Catalyzed Hydration of Alkenes
Alkenes react with water in the presence of an acid to form an alcohol. In the absence of acid, hydration of alkenes does not occur at a significant rate, and the acid is not consumed in the reaction. Therefore, alkene hydration is an acid-catalyzed reaction.
02:40Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
Introduction
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
02:35Acid-Catalyzed Dehydration of Alcohols to Alkenes
In a dehydration reaction, a hydroxyl group in an alcohol is eliminated along with the hydrogen from an adjacent carbon. Here, the products are an alkene and a molecule of water. Dehydration of alcohols is generally achieved by heating in the presence of an acid catalyst. While the dehydration of primary alcohols requires high temperatures and acid concentrations, secondary and tertiary alcohols can lose a water molecule under relatively mild conditions.
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,...
01:27Catalysis
Catalysis influences the rate of chemical reactions by providing an alternative reaction pathway with lower activation energy. A catalyst speeds up a reaction, but it is not consumed during the process. The fundamental principle of catalysis is the ability of a catalyst to alter the reaction mechanism, often introducing a more efficient pathway than the uncatalyzed process.In a catalyzed reaction, the catalyst participates directly in the reaction mechanism. It interacts with reactants to form...