Search results
Results from the WOW.Com Content Network
The protonation of isobutene in the formation of a carbocation: (CH 3) 2 C=CH 2 + HBF 4 ⇌ (CH 3) 3 C + + BF − 4; The protonation of ammonia in the formation of ammonium chloride from ammonia and hydrogen chloride: NH 3 + HCl → NH 4 Cl; Protonation is a fundamental chemical reaction and is a step in many stoichiometric and catalytic processes.
The reaction mechanism of the Mitsunobu reaction is fairly complex. The identity of intermediates and the roles they play has been the subject of debate. Initially, the triphenyl phosphine (2) makes a nucleophilic attack upon diethyl azodicarboxylate (1) producing a betaine intermediate 3, which deprotonates the carboxylic acid (4) to form the ion pair 5.
This has the effect of rendering the substrate more electrophilic and creating an ion pair, through which it is possible to transfer stereochemical information. Asymmetric catalysis involving nearly complete protonation of substrate has been effective in Mannich reactions of aromatic aldimines with carbon nucleophiles. [15]
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.
Reaction systems that are less efficient or entirely inactive in the absence of carboxylate acids and bases are likely to occur through a concerted metalation protonation reaction pathway. [15] An example of such a reaction with an sp 3 C–H bond that was reported in 2007 by Keith Fagnou and coworkers is an intramolecular cyclization that uses ...
Carbon fibers or carbon fibres (alternatively CF, graphite fiber or graphite fibre) are fibers about 5 to 10 micrometers (0.00020–0.00039 in) in diameter and composed mostly of carbon atoms. [1] Carbon fibers have several advantages: high stiffness, high tensile strength, high strength to weight ratio, high chemical resistance, high ...
The exchange reaction can be followed using a variety of methods (see Detection). Since this exchange is an equilibrium reaction, the molar amount of deuterium should be high compared to the exchangeable protons of the substrate. For instance, deuterium is added to a protein in H 2 O by diluting the H 2 O solution with D 2 O (e.g. tenfold ...
It is able to protonate butane to form tert-butyl cation at room temperature and is the only known acid to protonate carbon dioxide to give the bridged cation, [H(CO 2) 2] +, making it possibly the strongest known acid. In particular, CO 2 does not undergo observable protonation when treated with the mixed superacids HF-SbF 5 or HSO 3 F-SbF 5 ...