Question

n-heptane when heated to a temperature of about 773 K under high pressure in the presence of $C{r}_2{O}_3/A{l}_2{O}_3$ catalyst gives -

• A. Ethylbenzene
• B. 1,2-dimethylbenzene
• C. Benzene
• D. Methylbenzene(Toluene)

Answer 1

The correct option is D Methylbenzene(Toluene)

Aromatization:The n-alkanes with 6 or more C atoms, on heating to 773 K at 10-20 atm pressure in the presence of oxides of V/Mo/Cr get dehydrated and cyclised to form benzene and its derivatives.
$\underset{\text{n-heptane}}{C_7{H}_{16}}\underset{△\left(773K\right)}{\overset{C{r}_2{O}_3/A{l}_2{O}_3,10-20atm}{\to }}\underset{\text{Methylbenzene(Toluene)}}{C_6{H}_{5}C{H}_3}$