What is the Difference Between Benzene and Cyclohexane?

Benzene and cyclohexane are both cyclic hydrocarbon compounds with six carbon atoms. However, there are key differences between their structures and properties:

1. Aromaticity: Benzene is an aromatic compound, while cyclohexane is a non-aromatic compound. This means that benzene has a special stability due to its delocalized π electrons, which are shared by all six carbons in the ring. Cyclohexane, on the other hand, has no π electrons and is a saturated compound.
2. Double Bonds: Benzene has three double bonds with the formula C6H6, and these double bonds are conjugated with the rest of the molecule, forming an aromatic cycle. In contrast, cyclohexane has no double bonds and has the formula C6H12.
3. Structural Differences: The aromatic benzene ring is planar, meaning that all the carbon and hydrogen nuclei occupy the same plane. Cyclohexane, however, is not planar and has a slightly different geometry.
4. Stability: Benzene is more stable than cyclohexane due to its delocalized π electrons and aromatic nature. This stability is evident in the heats of hydrogenation, where benzene has a higher heat of hydrogenation compared to cyclohexane.
5. Reactivity: Benzene reacts more slowly with bromine than cyclohexane, forming a substitution product (C6H5Br) instead of the addition product (1,2-dibromocyclohexane) produced by cyclohexene. This difference in reactivity is due to benzene's aromaticity and delocalized π electrons.

In summary, the main differences between benzene and cyclohexane are their aromaticity, double bond arrangements, structural geometry, stability, and reactivity.

Comparative Table: Benzene vs Cyclohexane

Here is a table comparing the differences between benzene and cyclohexane:

Benzene is an aromatic compound with a molecular formula of C6H6, containing alternating single and double bonds, and has a planar structure. On the other hand, cyclohexane is a non-aromatic compound with a molecular formula of C6H12, containing only single bonds, and has a non-planar structure. Cyclohexane is more stable than benzene due to its full saturation and lower ring strain.