Question

What is the Gattermann Reaction?

Answer 1

Gattermann reaction:

• Gattermann reaction is used in the synthesis of aromatic compounds.
• Aromatic aldehyde, as well as aromatic halide, can be obtained from this reaction.
• “Chlorine or bromine can also be introduced in the benzene ring by treating the diazonium salt solution with corresponding halogen acid in the presence of copper powder. This is referred to as the Gatterman reaction.”
• The general Gattermann reaction can be depicted as:

$$\begin{gathered} \mathrm{Ar}\stackrel{+}{{\mathrm{N}}_2}\stackrel{-}{\mathrm{X}}\stackrel{\mathrm{Cu}/\mathrm{HCl}}{\to }\mathrm{ArCl}+{\mathrm{N}}_2+\mathrm{CuX} \\ \mathrm{or} \\ \mathrm{Ar}\stackrel{+}{{\mathrm{N}}_2}\stackrel{-}{\mathrm{X}}\stackrel{\mathrm{Cu}/\mathrm{HBr}}{\to }\mathrm{ArBr}+{\mathrm{N}}_2+\mathrm{CuX} \end{gathered}$$

Example of Gatermann's reaction:

• Chlorobenzene/bromobenzene can be obtained from benzene diazonium chloride by treating it with $\mathrm{Cu}/\mathrm{HCl}$ or $Br/HCl$ respectively.
• The reaction can be given as: