In acid-catalyzed Fischer esterification, the proton binds to oxygens and functions as a Lewis acid to activate the ester carbonyl (top row) as an electrophile, and converts the hydroxyl into the good leaving group water (bottom left). Both lower the kinetic barrier and speed up the attainment of chemical equilibrium.
In acid catalysis and base catalysis, a chemical reaction is catalyzed by an acid or a base. By Brønsted–Lowry acid–base theory, the acid is the proton (hydrogen ion, H+) donor and the base is the proton acceptor. Typical reactions catalyzed by proton transfer are esterifications and aldol reactions. In these reactions, the conjugate acid of the carbonyl group is a better electrophile than the neutral carbonyl group itself. Depending on the chemical species that act as the acid or base, catalytic mechanisms can be classified as either specific catalysis and general catalysis. Many enzymes operate by general catalysis.
In acidcatalysis and base catalysis, a chemical reaction is catalyzed by an acid or a base. By Brønsted–Lowry acid–base theory, the acid is the proton...
In Lewis acidcatalysis of organic reactions, a metal-based Lewis acid acts as an electron pair acceptor to increase the reactivity of a substrate. Common...
Catalysis (/kəˈtæləsɪs/) is the increase in rate of a chemical reaction due to an added substance known as a catalyst (/ˈkætəlɪst/). Catalysts are not...
In chemistry, homogeneous catalysis is catalysis where the catalyst is in same phase as reactants, principally by a soluble catalyst a in solution. In...
enzyme catalysis include general acid and base catalysis, orbital steering, entropic restriction, orientation effects (i.e. lock and key catalysis), as...
biochemistry, many enzymes employ acidcatalysis. Many biologically important molecules are acids. Nucleic acids, which contain acidic phosphate groups, include...
polystyrene sulfonate, solid phosphoric acid, niobic acid, and heteropolyoxometallates. Solid acids are used in catalysis in many industrial chemical processes...
by treatment with excess water under acid-catalyzed conditions: RO·OR−H3O−O; NR·H3O−O; RNR−H3O−O. Acidcatalysis can be applied to hydrolyses. For example...
A mineral acid (or inorganic acid) is an acid derived from one or more inorganic compounds, as opposed to organic acids which are acidic, organic compounds...
logarithmic scale used to specify the acidity or basicity of aqueous solutions. Acidic solutions (solutions with higher concentrations of hydrogen (H+) ions) are...
Acid strength is the tendency of an acid, symbolised by the chemical formula HA {\displaystyle {\ce {HA}}} , to dissociate into a proton, H + {\displaystyle...
+ CH3CH2OH → CH3CO2CH2CH3 + H2O The reaction can be accelerated by acidcatalysis and the equilibrium can be shifted to the right by removal of water...
by the Pinner reaction, in which nitriles react with alcohols under acidcatalysis: RCN + 3 R'OH → RC(OR')3 + NH3 Historically the prefixes "hypo-", "per-"...
Asymmetric Catalysis. Berlin; New York: Springer. pp. 1443–1445. ISBN 978-3-540-64336-4. Childs, R.F; Mulholland, D.L; Nixon, A. (1982). "Lewis acid adducts...
either acids or bases, the base-catalyzed reaction is more common. This path has lower reaction times and catalyst cost than those acidcatalysis. However...
(according to the original definition) is an acid with an acidity greater than that of 100% pure sulfuric acid (H2SO4), which has a Hammett acidity function...
functioning as a Lewis acid. Acidic oxides will typically have a low pKa and may be inorganic or organic. A commonly encountered acidic oxide, carbon dioxide...
silica. Some acid catalysed reactions include: the homogeneous catalysis of the hydrolysis of propene to give 2-propanol the homogeneous catalysis of the Prins...
laboratory conditions). Solutions with a pH value below 7.0 are considered acidic and solutions with pH value above 7.0 are basic. Since most naturally occurring...
ion promoted cleavage of RNA phosphodiester bonds involves a general acidcatalysis by the metal aquo ion on the departure of the leaving group". Journal...
In chemistry, an acid dissociation constant (also known as acidity constant, or acid-ionization constant; denoted K a {\displaystyle K_{a}} ) is a quantitative...
polyamides: Polyamides can also be synthesized from dinitriles using acidcatalysis via an application of the Ritter reaction. This method is applicable...
on dilution or if an acid or base is added at constant temperature. Its pH changes very little when a small amount of strong acid or base is added to it...
Global Information