Hydrogenation

Hydrogenation - to treat with hydrogen - is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically constitutes the addition of pairs of hydrogen atoms to a molecule, generally an alkene. Catalysts are required for the reaction to be usable; non-catalytic hydrogenation takes place only at very high temperatures. Hydrogen adds to double and triple bonds in hydrocarbons.

Because of the importance of hydrogen, many related reactions have been developed for its use. Most hydrogenations use gaseous hydrogen (H2), but some involve the alternative sources of hydrogen, not H2: these processes are called transfer hydrogenations. The reverse reaction, removal of hydrogen from a molecule, is called dehydrogenation. A reaction where bonds are broken while hydrogen is added is called hydrogenolysis, a reaction that may occur to carbon-carbon and carbon-heteroatom (oxygen, nitrogen or halogen) bonds. Hydrogenation differs from protonation or hydride addition: in hydrogenation, the products have the same charge as the reactants.

An illustrative example of a hydrogenation reaction is the addition of hydrogen to maleic acid to form succinic acid. Numerous important applications of this petrochemical are found in pharmaceutical and food industries. Hydrogenation of unsaturated fats produces saturated fats and, in some cases, trans fats.

Read more about Hydrogenation:  Process, Thermodynamics and Mechanism, Inorganic Substrates, Industrial Applications, Metal-free Hydrogenation, Equipment Used For Hydrogenation

Other articles related to "hydrogenation":

Equipment Used For Hydrogenation - Industrial Reactors
... Catalytic hydrogenation is done in a tubular plug-flow reactor (PFR) packed with a supported catalyst ... Catalyst loading is typically much lower than in laboratory batch hydrogenation, and various promoters are added to the metal, or mixed metals are used, to improve activity, selectivity and catalyst ... Gas Liquid Induction Reactors (Hydrogenator) are also used for carrying out catalytic hydrogenation ...
Organocatalytic Transfer Hydrogenation
... Organocatalytic transfer hydrogenation has been described by the group of List in 2004 in a system with a Hantzsch ester as proton donor and an amine catalyst Extending the scope of this reaction towards ... with most traditional metal based catalysts, hydrogenation of aromatic or heteroaromatic substrates tend to fail ...
Cluster Chemistry - Stereodynamics of Clusters - Appendix: Examples of Reactions Catalysed By Transition Metal Carbonyl Clusters
... Mo-Rh Mo2RhCp3(CO)5 Alkene hydroformylation Rh Rh4(CO)10+x(PPh3)2-x (x=0,2) CO hydrogenation Ru-Os H2RuOs3(CO)13 CO hydrogenation Ru-Co RuCo2(CO)11 CO hydrogenation Ir Ir4(CO)12 CO hydrogenation Fe Fe3(CO ...
Transfer Hydrogenation
... Transfer hydrogenation is the addition of hydrogen (H2 dihydrogen in inorganic and organometallic chemistry) to a molecule from a source other than gaseous H2 ... One large scale application of transfer hydrogenation is coal liquefaction using "donor solvents" such as tetralin ...
Migratory Insertion - Insertion of Alkenes Into M-H Bonds
... metal-hydrogen bonds is a key step in hydrogenation and hydroformylation reactions ... In hydrogenation, the resulting alkyl ligand combines with a second hydride to give the alkane ... Analogous reactions apply to the hydrogenation of alkynes a alkenyl ligand combines with a hydride to eliminate an alkene ...