Hydrogenation Catalysis
Hydrogenation Catalysis - Related Videos
02:50
Catalysis
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2020
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. The illustrated image represents the reaction diagrams for an endothermic chemical process progressing in the absence (red curve) and presence (blue curve) of a catalyst. Both...
01:27
Catalysis
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2026
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...
08:23
Introduction to Catalysis
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2015
Source: Laboratory of Dr. Ryan Richards — Colorado School of Mines Catalysis is among the most important fields of modern technology and presently accounts for approximately 35% of the gross domestic product (GDP) and sustenance of approximately 33% of the global population through fertilizers produced via the Haber process.1 Catalysts are systems that facilitate chemical reactions by lowering the activation energy and influencing the selectivity. Catalysis will be a central technology in...
08:56
Catalytic Reactor: Hydrogenation of Ethylene
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2023
Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA The hydrogenation of ethylene (C2H4) to ethane (C2H6) has often been studied as a model reduction reaction in characterizing new metal catalysts.1-2 While supported nickel is not the most active metal catalyst for this reaction, it is active enough that reaction can take place at < 200°C. The reaction typically involves adsorbed, dissociated hydrogen (H2) reacting...
06:06
Hydrogenation
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2023
Source: Vy M. Dong and Zhiwei Chen, Department of Chemistry, University of California, Irvine, CA This experiment will demonstrate the hydrogenation of chalcone as an example of an alkene hydrogenation reaction (Figure 1). In this experiment, palladium on carbon (Pd/C) will be used as a heterogeneous catalyst for the process. A balloon will be used to supply the hydrogen atmosphere. Figure 1: Diagram showing the hydrogenation of chalcone to 3-phenylpropiophenone.
FAQs
The catalyst provides a coordinated environment in which hydrogen and the unsaturated substrate can interact. Metal binding helps activate the H–H bond, allowing hydrogen atoms to transfer stepwise rather than requiring direct reaction between the original reactants. This catalytic pathway can improve reaction rate while giving chemists greater control over selectivity and limiting unwanted byproducts.
Stepwise transfer creates opportunities to control how hydrogen adds across an unsaturated site. For alkenes, alkynes, and carbonyl compounds, the catalyst-mediated sequence helps direct the transformation toward the intended product instead of allowing less controlled reaction pathways. This control is important when a process must manage reaction rate, regioselectivity, or stereoselectivity.
Palladium, platinum, nickel, and rhodium can all serve as catalyst bases for hydrogenation transformations, but catalyst design determines how effectively the process balances rate and selectivity. The relevant choice depends on the desired chemical transformation and the need to limit unwanted products. Comparing metal-based systems therefore helps tailor hydrogenation to a particular substrate or manufacturing goal.
Two major outcomes are regioselectivity and stereoselectivity. Regioselectivity concerns which position in a molecule is transformed, whereas stereoselectivity concerns the spatial arrangement of the resulting product. Catalyst design can also reduce unwanted byproducts. Managing these outcomes is especially valuable in organic synthesis, where closely related products may differ substantially in usefulness.
A typical sequence begins when hydrogen and the substrate bind to the metal catalyst. The catalyst then activates the H–H bond, transfers hydrogen atoms stepwise to the unsaturated bond, and releases the product. This sequence connects the molecular events to the observed catalytic performance, including the reaction rate and the selectivity achieved for the intended transformation.
Hydrogenation catalysis supports organic synthesis, petroleum processing, and the manufacture of pharmaceuticals, polymers, and specialty chemicals. Its value extends beyond accelerating reactions: catalyst design can help reduce energy use and suppress unwanted byproducts. These features make the approach relevant both to laboratory transformations and to larger chemical processes that require controlled production of useful materials.
The approach applies to several classes of unsaturated molecules, including alkenes, alkynes, and carbonyl compounds. This range gives hydrogenation catalysis broad relevance in chemistry because different substrate classes can be processed through related catalyst-mediated hydrogen transfer events. The selected catalyst and its design influence how effectively the reaction rate and product selectivity are controlled for each class.