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Halogenation of benzene where X is the halogen, catalyst represents the catalyst (if needed) and HX represents the protonated base. A few types of aromatic compounds, such as phenol, will react without a catalyst, but for typical benzene derivatives with less reactive substrates, a Lewis acid is required as a catalyst.
In chemistry, halogenation is a chemical reaction which introduces one or more halogens into a chemical compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs. [1] This kind of conversion is in fact so common that a comprehensive overview is challenging.
In chemistry, the haloform reaction (also referred to as the Lieben haloform reaction) is a chemical reaction in which a haloform (CHX 3, where X is a halogen) is produced by the exhaustive halogenation of an acetyl group (R−C(=O)CH 3, where R can be either a hydrogen atom, an alkyl or an aryl group), in the presence of a base.
A good example of a substitution reaction is halogenation. When chlorine gas (Cl 2) is irradiated, some of the molecules are split into two chlorine radicals (Cl•), whose free electrons are strongly nucleophilic. One of them breaks a C–H covalent bond in CH 4 and grabs the hydrogen atom to form the electrically neutral HCl.
More recently, trifluoromethylation of diazonium salts has been developed and is referred to as a 'Sandmeyer-type' reaction. Diazonium salts also react with boronates, iodide, thiols, water, hypophosphorous acid and others, [6] and fluorination can be carried out using tetrafluoroborate anions (Balz–Schiemann reaction). However, since these ...
The most widely practised example of this reaction is the ethylation of benzene. Approximately 24,700,000 tons were produced in 1999. [2] (After dehydrogenation and polymerization, the commodity plastic polystyrene is produced.) In this process, acids are used as catalyst to generate the incipient carbocation. Many other electrophilic reactions ...
A chlorophenol is any organochloride of phenol that contains one or more covalently bonded chlorine atoms. There are five basic types of chlorophenols (mono- to pentachlorophenol) and 19 different chlorophenols in total when positional isomerism is taken into account. Chlorophenols are produced by electrophilic halogenation of phenol with ...
For example, phenols and anilines react quickly with chlorine and bromine water to give multihalogenated products. Many detailed laboratory procedures are available. [ 5 ] For alkylbenzene derivatives, e.g. toluene , the alkyl positions tend to be halogenated by free radical conditions, whereas ring halogenation is favored in the presence of ...