ゼオライトの分子化学:ゼオライトのYで支えられたルテニウム複合体の触媒の起源
1Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, USA.
Journal of the American Chemical Society
|September 13, 2008
まとめ
非発光ゼオライトYは,安定したエチレン二重化のために単核ルテニウム複合体をサポートします. ゼオライトアルミニウムサイトと水素ガスの間の協力は,触媒活性を大幅に高めます.
科学分野:
- 異質なカタリシスである.
- マテリアルサイエンス 材料科学
- 協調化化学について
背景:
- ゼオライトは,触媒の支柱として広く使用されています.
- 脱光化などのゼオライトの特性を調節すると,触媒性能が変化する.
- ルテニウム複合体は,様々な触媒変換の可能性を秘めています.
研究 の 目的:
- 非発光ゼオライトYに固定された単核ルテニウム複合体を合成し,特徴づけること.
- エチレン二酸化のためのこれらのサポートされた複合体の触媒的活性を調べる.
- 触媒サイクルにおけるゼオライト構造とコリアクタントの役割を明らかにする.
主な方法:
- 単核ルテニウム複合体の合成:cis-Ru(acac) 2 ((C2H4) 2.
- 複合体を非発光ゼオライトYに固定する.
- 赤外線 (IR) と拡張X線吸収微細構造 (EXAFS) のスペクトロスコーピーを用いた特徴付け.
- 添加水素と添加水素なしのエチレン二酸化のための触媒試験.
主要な成果:
- 単核ルテニウム複合体,Ru ((acac) (((C2H4) 2 (((2+) は,Ru-O結合経由でアル (((3+) 部位へのRu-O結合経由で非発光ゼオライトYに成功裏に固定されました.
- 達成された最大負荷は,2つのAl3+) サイトごとに1つの複合体であった;より高い負荷は物理吸収をもたらした.
- エチレン二酸化は,水素コーフィードで約600倍速く,シネージー効果を示しました.
- アカックリンガンドは解離し,反応の開始時にAl ((3+) サイトによって捕獲された.
結論:
- 非発光ゼオライトYは,精密な触媒合成のための非常に効果的で均一なサポートとして機能します.
- ゼオライトAl ((3+) サイトとコフード水素の間の協力は,活性な触媒種を生成するために不可欠です.
- サポートされた単核ルテニウム複合体は,安定した,非常に効率的なエチレン二酸化触媒を示す.
関連する概念動画
01:22Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...
01:17Ziegler–Natta Chain-Growth Polymerization: Overview
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 catalyst, high molecular...
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...
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.
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...
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
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...