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Hydrogenation is a chemical reaction between molecular hydrogen (H 2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically constitutes the addition of pairs of hydrogen atoms to a molecule ...
Heterogeneous catalysis typically involves solid phase catalysts and gas phase reactants. [2] In this case, there is a cycle of molecular adsorption, reaction, and desorption occurring at the catalyst surface. Thermodynamics, mass transfer, and heat transfer influence the rate (kinetics) of reaction.
In heterogeneous catalysis, hydrogen molecules can be adsorbed and dissociated by the metal catalyst. Hydrogen spillover is the migration of hydrogen atoms from the metal catalyst onto the nonmetal support or adsorbate. [1] [2] Spillover, generally, is the transport of a species adsorbed or formed on a surface onto another surface. [3]
Plucinkski and coworkers developed a continuous Mizoroki-Heck and hydrogenation sequence consisting of two separated packed-bed reactors containing Pd/C. [15] Because the Pd/C-catalyzed hydrogenation proceeds via a heterogeneous mechanism, [16] metal leaching due to the second hydrogenation step is minimal, and Pd leached from the first part of ...
Heterogeneous catalytic reactors put emphasis on catalyst effectiveness factors and the heat and mass transfer implications. Heterogeneous catalytic reactors are ...
First reactor at the Oppau plant in 1913 Profiles of the active components of heterogeneous catalysts; the top right figure shows the profile of a shell catalyst. The Haber–Bosch process relies on catalysts to accelerate N 2 hydrogenation. The catalysts are heterogeneous solids that interact with gaseous reagents. [41]
An illustrative example is the effect of catalysts to speed the decomposition of hydrogen peroxide into water and oxygen: . 2 H 2 O 2 → 2 H 2 O + O 2. This reaction proceeds because the reaction products are more stable than the starting compound, but this decomposition is so slow that hydrogen peroxide solutions are commercially available.
An electrocatalyst can be heterogeneous such as a platinized electrode. [1] Homogeneous electrocatalysts, which are soluble, assist in transferring electrons between the electrode and reactants, and/or facilitate an intermediate chemical transformation described by an overall half reaction. [2] Major challenges in electrocatalysts focus on fuel ...