What is the difference between aliphatic and aromatic compounds?

1 Answer
Oct 31, 2016

Well, an aromatic compound has 4 degrees of unsaturation....What does this mean?

Explanation:

A saturated, unsubstituted hydrocarbon has a formula of CnH2n+2. Alkanes are said to be saturated. Try this out with methane, ethane, propane, etc. Each double bond, or ring junction, reduces the hydrogen count by 2, and so introduces 1 degree of unsaturation. Cyclohexane or hexene thus have formulae of C6H12.

Aromatic compounds generally feature the benzene ring, which imposes 4 degrees of unsaturation; i.e. consider the benzene molecule, C6H6, where hexane would by C6H14. The extra electron density on the aromatic ring (the six delocalized π electrons) offers peculiar chemisty; distinct from the chemistry of the alkanes.