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Electrophilic aromatic substitution (S E Ar) is an organic reaction in which an atom that is attached to an aromatic system (usually hydrogen) is replaced by an electrophile. Some of the most important electrophilic aromatic substitutions are aromatic nitration , aromatic halogenation , aromatic sulfonation , alkylation Friedel–Crafts ...
The inductive and resonance properties compete with each other but the resonance effect dominates for purposes of directing the sites of reactivity. For nitration, for example, fluorine directs strongly to the para position because the ortho position is inductively deactivated (86% para, 13% ortho, 0.6% meta).
In electrophilic substitution in aromatic compounds, an atom appended to the aromatic ring, usually hydrogen, is replaced by an electrophile. The most important reactions of this type that take place are aromatic nitration, aromatic halogenation, aromatic sulfonation and acylation and alkylating Friedel-Crafts reactions. It further consists of ...
Methyl nitrate is a very strong explosive with a detonation velocity of 6,300 m/s, [8] like nitroglycerin, ethylene glycol dinitrate, and other nitrate esters. The sensitivity of methyl nitrate to initiation by detonation is among the greatest known, with even a number one blasting cap , the lowest power available, producing a near full ...
The phrase ipso nitration was first used by Perrin and Skinner in 1971, in an investigation into chloroanisole nitration. [18] In one protocol, 4-chloro- n -butylbenzene is reacted with sodium nitrite in t -butanol in the presence of 0.5 mol% Pd 2 (dba) 3 , a biarylphosphine ligand and a phase-transfer catalyst to provide 4-nitro- n -butylbenzene.
The nitration product produced on the largest scale, by far, is nitrobenzene. Many explosives are produced by nitration including trinitrophenol (picric acid), trinitrotoluene (TNT), and trinitroresorcinol (styphnic acid). [3] Another but more specialized method for making aryl–NO 2 group starts from halogenated phenols, is the Zinke nitration.
Methylation, in the chemical sciences, is the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These terms are commonly used in chemistry, biochemistry, soil science, and biology.
The oxidation products derived from methyl are hydroxymethyl group −CH 2 OH, formyl group −CHO, and carboxyl group −COOH. For example, permanganate often converts a methyl group to a carboxyl (−COOH) group, e.g. the conversion of toluene to benzoic acid. Ultimately oxidation of methyl groups gives protons and carbon dioxide, as seen in ...