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It can also be synthesized in the laboratory. To do so, sodium hydroxide and bromine are added to an ice-water solution of succinimide. The NBS product precipitates and can be collected by filtration. [2] Crude NBS gives better yield in the Wohl–Ziegler reaction. In other cases, impure NBS (slightly yellow in color) may give unreliable results.
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.
Benzonitrile is a useful solvent and a versatile precursor to many derivatives. It reacts with amines to afford N-substituted benzamides after hydrolysis. [3] It is a precursor to diphenylmethanimine via reaction with phenylmagnesium bromide followed by methanolysis.
Due to the high toxicity and ozone-depleting nature of carbon tetrachloride, trifluorotoluene has been proposed as an alternative solvent suitable for the Wohl-Ziegler bromination. [ 6 ] The corresponding chlorination reaction cannot generally be achieved with N- chlorosuccinimide, [ 7 ] although more specialized reagents have been developed ...
The reaction mechanism for chlorination of benzene is the same as bromination of benzene. Iron(III) bromide and iron(III) chloride become inactivated if they react with water, including moisture in the air. Therefore, they are generated by adding iron filings to bromine or chlorine. Here is the mechanism of this reaction:
A halogen addition reaction is a simple organic reaction where a halogen molecule is added to the carbon–carbon double bond of an alkene functional group. [1]The general chemical formula of the halogen addition reaction is:
An example of the Hell–Volhard–Zelinsky reaction can be seen in the preparation of alanine from propionic acid.In the first step, a combination of bromine and phosphorus tribromide is used in the Hell–Volhard–Zelinsky reaction to prepare 2-bromopropionic acid, [3] which in the second step is converted to a racemic mixture of the amino acid product by ammonolysis.
These methods work best when the bromide product is stable to hydrolysis; otherwise, the possibilities include high-temperature oxidative bromination of the element with bromine or hydrogen bromide, high-temperature bromination of a metal oxide or other halide by bromine, a volatile metal bromide, carbon tetrabromide, or an organic bromide.