The process described encompasses the Sandmeyer and Balz-Schiemann reactions, resulting in the synthesis of fluorobenzene and nitrobenzene.
Step 1: Balz-Schiemann Reaction (Fluorination) Initially, benzene diazonium chloride is reacted with HBF\(_4\) to yield benzene diazonium tetrafluoroborate. \[\text{C}_6\text{H}_5\text{N}_2^+Cl^- + HBF_4 \rightarrow \text{C}_6\text{H}_5\text{N}_2^+BF_4^-\]Subsequent heating of this intermediate leads to its decomposition, producing fluorobenzene, nitrogen gas, and boron trifluoride. \[\text{C}_6\text{H}_5\text{N}_2^+BF_4^- \xrightarrow{\Delta} \text{C}_6\text{H}_5F + N_2 + BF_3\]Step 2: Sandmeyer Reaction (Nitration) The subsequent step involves treating benzene diazonium chloride with NaNO\(_2\) in the presence of copper catalyst and heat. This reaction substitutes the diazonium group with a nitro (-NO\(_2\)) moiety, forming nitrobenzene. \[\text{C}_6\text{H}_5\text{N}_2^+Cl^- + NaNO_2/Cu, \Delta \rightarrow \text{C}_6\text{H}_5NO_2 + N_2\]