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Organic redox reaction
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<p>Organic reductions or organic oxidations or organic redox reactions are <a href="/facts/Redox_reaction/Pyd5RVcj">redox reactions</a> that take place with <a href="/facts/Organic_compound/gqCNaN45">organic compounds</a>. In <a href="/facts/Organic_chemistry/djxhxaNg">organic chemistry</a> oxidations and reductions are different from ordinary redox reactions, because many reactions carry the name but do not actually involve <a href="/facts/Electron_transfer/BIdASS9R">electron transfer</a>. Instead the relevant criterion for organic oxidation is gain of oxygen and/or loss of hydrogen. Simple <a href="/facts/Functional_groups/GXkSPsjM">functional groups</a> can be arranged in order of increasing <a href="/facts/Oxidation_state/W53W6s6V">oxidation state</a>. The <a href="/facts/Oxidation_numbers/W53W6s6V">oxidation numbers</a> are only an approximation: </p> <table><tbody><tr><th>oxidation number</th><th>compounds</th></tr><tr><td>−4</td><td><a href="/facts/Methane/kBHneYnh">methane</a></td></tr><tr><td>−3</td><td><a href="/facts/Alkane/Qam7Hvmf">alkanes</a></td></tr><tr><td>−2, −1</td><td><a href="/facts/Alkane/Qam7Hvmf">alkanes</a>, <a href="/facts/Alkene/RtYcS6kU">alkenes</a>, <a href="/facts/Alcohol_(chemistry)/Y0SCTDkh">alcohols</a>, <a href="/facts/Alkyl_halide/Enb7LQqt">alkyl halides</a>, <a href="/facts/Amine/JvfYJfP6">amines</a></td></tr><tr><td>0</td><td><a href="/facts/Alkyne/VHI4N5Wo">alkynes</a>, <a href="/facts/Geminal_diol/1cv1vEBN">geminal diols</a></td></tr><tr><td>+1</td><td><a href="/facts/Aldehydes/xSIRkW03">aldehydes</a></td></tr><tr><td>+2</td><td><a href="/facts/Chloroform/gvzuJMXa">chloroform</a>, <a href="/facts/Hydrogen_cyanide/vNtA0Mxe">hydrogen cyanide</a>, <a href="/facts/Ketone/BqQXpLo4">ketones</a></td></tr><tr><td>+3</td><td><a href="/facts/Carboxylic_acid/U4xuMosy">carboxylic acids</a>, <a href="/facts/Amide/C6kCzYEA">amides</a>, <a href="/facts/Nitrile/Gz7RCnC6">nitriles</a> (alkyl cyanides)</td></tr><tr><td>+4</td><td><a href="/facts/Carbon_dioxide/xGzpppEp">carbon dioxide</a>, <a href="/facts/Tetrachloromethane/S2ekjT0E">tetrachloromethane</a></td></tr></tbody></table> <p>When <a href="/facts/Methane/kBHneYnh">methane</a> is oxidized to <a href="/facts/Carbon_dioxide/xGzpppEp">carbon dioxide</a> its oxidation number changes from −4 to +4. Classical reductions include <a href="/facts/Alkene/RtYcS6kU">alkene</a> reduction to <a href="/facts/Alkane/Qam7Hvmf">alkanes</a> and classical oxidations include <a href="/facts/Alcohol_oxidation/FV12dlnW">oxidation of alcohols</a> to <a href="/facts/Aldehyde/xSIRkW03">aldehydes</a>. In oxidations electrons are removed and the electron density of a molecule is reduced. In reductions electron density increases when electrons are added to the molecule. This terminology is always centered on the organic compound. For example, it is usual to refer to the reduction of a <a href="/facts/Ketone/BqQXpLo4">ketone</a> by <a href="/facts/Lithium_aluminium_hydride/QMMhdqEy">lithium aluminium hydride</a>, but not to the oxidation of lithium aluminium hydride by a ketone. Many oxidations involve removal of hydrogen atoms from the organic molecule, and reduction adds hydrogens to an organic molecule. </p><p>Many reactions classified as reductions also appear in other classes. For instance, conversion of the ketone to an alcohol by lithium aluminium hydride can be considered a reduction but the hydride is also a good <a href="/facts/Nucleophile/xYccoaJQ">nucleophile</a> in <a href="/facts/Nucleophilic_substitution/MLLeSsnr">nucleophilic substitution</a>. Many redox reactions in organic chemistry have <a href="/facts/Coupling_reaction/L464wvvk">coupling reaction</a> <a href="/facts/Reaction_mechanism/9lanyVuy">reaction mechanism</a> involving <a href="/facts/Free_radical/qFymuVoT">free radical</a> intermediates. True organic redox chemistry can be found in electrochemical organic synthesis or <a href="/facts/Electrosynthesis/hzU3XYxC">electrosynthesis</a>. Examples of organic reactions that can take place in an <a href="/facts/Electrochemical_cell/o7oEnYVl">electrochemical cell</a> are the <a href="/facts/Kolbe_electrolysis/NakYsFj5">Kolbe electrolysis</a>. </p><p>In disproportionation reactions the reactant is both oxidised and reduced in the same chemical reaction forming two separate compounds. </p><p><a href="/facts/Asymmetric_catalytic_reduction/aEUM1Knh">Asymmetric catalytic reductions</a> and <a href="/facts/Asymmetric_catalytic_oxidation/bNGCrbJ4">asymmetric catalytic oxidations</a> are important in <a href="/facts/Asymmetric_synthesis/5hJe37TL">asymmetric synthesis</a>. </p>