Century Aromatics

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Cyanogen bromide is a pseudohalogen compound with the formula CNBr. It is a colorless solid that is widely used to modify bio polymers, fragment proteins and peptides and synthesize other compounds.

Although the formula is most commonly written CNBr, the carbon atom is actually bonded to bromine by a single bond and to nitrogen by a triple bond (i.e. Br–C≡N). The compound is linear and quite polar, but it does not spontaneously ionize in water. Therefore, it dissolves in both water and polar organic solvents.

Cyanogen bromide can be prepared by oxidation of sodium cyanide with bromine, which proceeds in two steps via the intermediate cyanogen ((CN)₂ or N≡C–C≡N).

2 NaCN + Br₂ → (CN)₂ + 2 NaBr (CN)₂ + Br₂ → 2 BrCN
Cyanogen bromide is hydrolyzed by water to release hydrogen cyanide and hypobromous acid BrCN + H₂O → HCN + HOBr