Benzenediazonium chloride

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Benzenediazonium chloride
IUPAC name Benzenediazonium chloride
Other names Phenyldiazonium chloride
Identifiers
CAS number [100-34-5]
SMILES [Cl-].N#[N+]c1ccccc1
Properties
Molecular formula C6H5ClN2
Molar mass 140.570 g/mol
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Benzenediazonium chloride is the diazonium compound of aniline. It is used in the preparation of azo compounds (e.g. azo dyes). It is synthesised from nitrous acid and aniline. Nitrous acid is prepared in situ due to the fact that it is not stable enough to be stored.

[edit] Synthesis

Preparation of nitrous acid:

NaNO2 + HCl → HNO2 + NaCl

The nitrous acid formed is reacted with aniline to give benzenediazonium chloride:

C6H5NH2 + HNO2 + HCl → [C6H5N+≡N][Cl]

The temperature must be kept between 0-5 °C to avoid the product from reacting and forming dinitrogen.

[edit] Diazo coupling reactions

Benzenediazonium chloride can react with phenol or aniline, via diazo coupling reactions, to give azo compounds: