完全な同位体選択性への経路:アルミニウム改性メソポラスシリカ (MCF-17) をサポートしたプラチナナノ粒子のn-ヘクサン変換 (リフォーム)
Nathan Musselwhite1, Kyungsu Na, Selim Alayoglu
1Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States.
Journal of the American Chemical Society
|November 12, 2014
まとめ
アルミニウム改変シリカ (MCF-17) をプラチナナノ粒子と組み合わせると,n-ヘクサンイソメリゼーションの高度に活性な触媒を生み出します. このタンデム触媒は,高温下でも90%以上の選択性を達成します.
科学分野:
- マテリアルサイエンス 材料科学
- カタリシス カタリシス カタリシス
- ナノテクノロジー ナノテクノロジー
背景:
- メソポラスシリカ (MCF-17) は,触媒の汎用性のある材料です.
- アルミニウムの改造により,ルイス酸のサイトが作られる.
- プラチナナノ粒子は,炭化水素変換の触媒として知られています.
研究 の 目的:
- n-ヘクサンのイソメリゼーションのための高度に活性で選択的な触媒を開発する.
- 酸性支柱と金属ナノ粒子の相乗効果を調査する.
- 高温下での触媒性能を調査するために.
主な方法:
- アルミニウム改変メソポラスシリカ (アルミ改変MCF-17) の合成.
- コロイド合成プラチナナノ粒子をMCF-17およびアルミニウム改変MCF-17.7にロードする.
- 240~360°Cでのn-ヘクサンのリフォームにおける触媒活性と選択性の評価.
主要な成果:
- アルミニウム改変した純粋なMCF-17は,n-ヘクサンイソメリゼーションの活性を示さなかった.
- 伝統的なMCF-17のプラチナナノ粒子は,非常に低い異体化活性を示しました.
- アルミニウム改変されたMCF-17のプラチナナノ粒子は, >90%の選択性を持つ支配的な異体化経路を示した.
結論:
- 酸性Al変形MCF-17とプラチナナノ粒子を組み合わせたタンデム触媒システムは,n-ヘクサンのイソメリゼーションに非常に効果的です.
- サポートと金属ナノ粒子の間の相乗効果の相互作用は,高い活性と選択性にとって不可欠です.
- この触媒系は,高温で効率的な炭化水素同位体生成の有望性を示しています.
関連する概念動画
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
4.1K
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...
4.1K
02:13Reduction of Alkenes: Catalytic Hydrogenation
15.3K
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
15.3K
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
13.9K
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
13.9K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
9.8K
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.
9.8K
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
19.2K
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
19.2K
01:28Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation
6.6K
Unlike the easy catalytic hydrogenation of an alkene double bond, hydrogenation of a benzene double bond under similar reaction conditions does not take place easily. For example, in the reduction of stilbene, the benzene ring remains unaffected while the alkene bond gets reduced. Hydrogenation of an alkene double bond is exothermic and a favorable process. In contrast, to hydrogenate the first unsaturated bond of benzene, an energy input is needed; that is, the process is endothermic. This is...
6.6K