Chlorobenzene from Aniline via the Sandmeyer Reaction 

Chlorobenzene is a useful chemical in organic syntheses. It dissolves a wide range of organic compounds, making it an effective high-boiling solvent. It also has numerous applications as a reagent. For example, it is a direct precursor to phenylmagnesium chloride, a valuable Grignard reagent that can be used to produce a variety of compounds (e.g. benzene, triphenylmethanol, etc.).
The most common laboratory preparation of chlorobenzene involves the direct chlorination of benzene using a Lewis acid catalyst. This preparation is considerably hazardous, as it involves the use of very toxic and carcinogenic chemicals. For home chemists, a safer method of preparing chlorobenzene is the use of the Sandmeyer reaction. This reaction entails the diazotization of aniline to a phenyldiazonium salt, followed by the catalytic decomposition of that salt with copper(I) chloride. The main resultant product is chlorobenzene.
In this experiment, chlorobenzene will be prepared from aniline via the Sandmeyer reaction, as detailed above.