JEE Main & Advanced Chemistry Hydrocarbons / हाइड्रोकार्बन Aromatic Hydrocarbon

(1) Source of Arenes

Source of arenes is coal. It contains benzene, xylene, naphthalene etc. Arenes are obtained by destructive distillation of coal.

(2) Distillation of coal

• Coal tar is a mixture of large numbers of arenes.

(3) Distillation of coal tar : Arenes are isolated by fractional distillation of coal tar,  

• The residue left after fractional distillation of coal-tar is called pitch.

(4) Isolation of benzene             

\[\text{Light}\,\text{oil}\xrightarrow{\text{cold }{{H}_{2}}S{{O}_{4}}}\begin{matrix}\underset{\text{ }\!\![\!\!\text{ Like pyridene }\!\!]\!\!\text{ }}{\mathop{\text{Basic impurities removed }}}\,  \\\end{matrix}\xrightarrow{NaOH}\]

\[\underset{\text{ }\!\![\!\!\text{ Acidic impurities }\!\!]\!\!\text{ }}{\mathop{\begin{matrix} \text{Phenols removed}  \\ \end{matrix}}}\,\xrightarrow{\text{distillation}}\begin{matrix} \underset{\text{Toluene (383 }K\text{)}\,\,\,\,\,\,\,\,\,\,}{\mathop{\text{Benzene (255-257}K\text{)}}}\,\text{ }  \\ \end{matrix}\]