In chemistry, protonation (or hydronation) is the adding of a proton (or hydron, or hydrogen cation), (H+) to an atom, molecule, or ion, forming a conjugate acid.[1] (The complementary process, when a proton is removed from a Brønsted–Lowry acid, is deprotonation.) Some examples include
Protonation is a fundamental chemical reaction and is a step in many stoichiometric and catalytic processes. Some ions and molecules can undergo more than one protonation and are labeled polybasic, which is true of many biological macromolecules. Protonation and deprotonation (removal of a proton) occur in most acid–base reactions; they are the core of most acid–base reaction theories. A Brønsted–Lowry acid is defined as a chemical substance that protonates another substance. Upon protonating a substrate, the mass and the charge of the species each increase by one unit, making it an essential step in certain analytical procedures such as electrospray mass spectrometry. Protonating or deprotonating a molecule or ion can change many other chemical properties, not just the charge and mass, for example solubility, hydrophilicity, reduction potential, and optical properties can change.
Protonations are often rapid, partly because of the high mobility of protons in many solvents. The rate of protonation is related to the acidity of the protonating species: protonation by weak acids is slower than protonation of the same base by strong acids. The rates of protonation and deprotonation can be especially slow when protonation induces significant structural changes.[2]
Reversibility and catalysis
Protonation is usually reversible, and the structure and bonding of the conjugate base are normally unchanged on protonation. In some cases, however, protonation induces isomerization, for example cis-alkenes can be converted to trans-alkenes using a catalytic amount of protonating agent. Many enzymes, such as the serine hydrolases, operate by mechanisms that involve reversible protonation of substrates.
^Zumdahl, S. S. (1986). Chemistry. Lexington, MA: Heath. ISBN0-669-04529-2.
^Kramarz, K. W.; Norton, J. R. (1994). "Slow Proton Transfer Reactions in Organometallic and Bioinorganic Chemistry". Progress in Inorganic Chemistry. 42: 1–65. doi:10.1002/9780470166437.ch1.
March 02, 2023
protonation, chemistry, protonation, hydronation, adding, proton, hydron, hydrogen, cation, atom, molecule, forming, conjugate, acid, complementary, process, when, proton, removed, from, brønsted, lowry, acid, deprotonation, some, examples, include, protonatio. In chemistry protonation or hydronation is the adding of a proton or hydron or hydrogen cation H to an atom molecule or ion forming a conjugate acid 1 The complementary process when a proton is removed from a Bronsted Lowry acid is deprotonation Some examples include The protonation of water by sulfuric acid H2SO4 H2O H3O HSO 4 The protonation of isobutene in the formation of a carbocation CH3 2C CH2 HBF4 CH3 3C BF 4 The protonation of ammonia in the formation of ammonium chloride from ammonia and hydrogen chloride NH3 g HCl g NH4Cl s Protonation is a fundamental chemical reaction and is a step in many stoichiometric and catalytic processes Some ions and molecules can undergo more than one protonation and are labeled polybasic which is true of many biological macromolecules Protonation and deprotonation removal of a proton occur in most acid base reactions they are the core of most acid base reaction theories A Bronsted Lowry acid is defined as a chemical substance that protonates another substance Upon protonating a substrate the mass and the charge of the species each increase by one unit making it an essential step in certain analytical procedures such as electrospray mass spectrometry Protonating or deprotonating a molecule or ion can change many other chemical properties not just the charge and mass for example solubility hydrophilicity reduction potential and optical properties can change Contents 1 Rates 2 Reversibility and catalysis 3 See also 4 ReferencesRates EditProtonations are often rapid partly because of the high mobility of protons in many solvents The rate of protonation is related to the acidity of the protonating species protonation by weak acids is slower than protonation of the same base by strong acids The rates of protonation and deprotonation can be especially slow when protonation induces significant structural changes 2 Reversibility and catalysis EditProtonation is usually reversible and the structure and bonding of the conjugate base are normally unchanged on protonation In some cases however protonation induces isomerization for example cis alkenes can be converted to trans alkenes using a catalytic amount of protonating agent Many enzymes such as the serine hydrolases operate by mechanisms that involve reversible protonation of substrates See also EditAcid dissociation constant Deprotonation or dehydronation Molecular autoionizationReferences Edit Zumdahl S S 1986 Chemistry Lexington MA Heath ISBN 0 669 04529 2 Kramarz K W Norton J R 1994 Slow Proton Transfer Reactions in Organometallic and Bioinorganic Chemistry Progress in Inorganic Chemistry 42 1 65 doi 10 1002 9780470166437 ch1 Retrieved from https en wikipedia org w index php title Protonation amp oldid 1122867302, wikipedia, wiki, book, books, library,
