Search results
Results from the WOW.Com Content Network
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.
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.
For example, consider radical bromination of toluene: [5] bromination of toluene with hydrobromic acid and hydrogen peroxide in water. This reaction takes place on water instead of an organic solvent and the bromine is obtained from oxidation of hydrobromic acid with hydrogen peroxide. An incandescent light bulb suffices to radicalize.
Toluene (or methylbenzene) is a common chemical found in chemistry laboratories. An alkylbenzene is a chemical compound that contains a monocyclic aromatic ring attaching to one or more saturated hydrocarbon chains. [1] Alkylbenzenes are derivatives of benzene, in which one or more hydrogen atoms are replaced by alkyl groups.
The decolouration of bromine water by electron-rich arenes is used in the bromine test. Reaction between benzene and halogen to form an halogenobenzene. The oxychlorination of benzene has been well investigated, motivated by the avoidance of HCl as a coproduct in the direct halogenation: [3] 4 C 6 H 6 + 4 HCl + O 2 → 4 C 6 H 5 Cl + H 2 O
Regiochemistry follows from the reaction mechanism, which exhibits halogen attack on the least-hindered unsaturated carbon. The mechanism for this chain reaction resembles free radical halogenation, in which the peroxide promotes formation of the bromine radical. However, this process is restricted to addition of HBr.
An example is the conversion of alkyl chloride into alkyl fluoride: C 3 H 5-Cl + NaF → R-F + NaCl. This kind of reaction is called Finkelstein reaction. [2] However, it is also possible, for example, to produce phosphorus fluoride compounds by transhalogenating chlorine, bromine or iodine bound to phosphorus with a metal fluoride. [3]
The reaction begins with the formation of alkyl/arene-magnesium-halogen compound, followed by addition of proton source to form dehalogenated product. Egorov and his co-workers have reported dehalogenation of benzyl halides using atomic magnesium in 3P state at 600 °C. Toluene and bi-benzyls were produced as the product of the reaction. [9]