Aromatic Hydrocarbon - Benzene and Derivatives of Benzene

Benzene and Derivatives of Benzene

Benzene derivatives have from one to six substituents attached to the central benzene core. Examples of benzene compounds with just one substituent are phenol, which carries a hydroxyl group, and toluene with a methyl group. When there is more than one substituent present on the ring, their spatial relationship becomes important for which the arene substitution patterns ortho, meta, and para are devised. For example, three isomers exist for cresol because the methyl group and the hydroxyl group can be placed next to each other (ortho), one position removed from each other (meta), or two positions removed from each other (para). Xylenol has two methyl groups in addition to the hydroxyl group, and, for this structure, 6 isomers exist.

• Representative arene compounds

• Toluene

• Ethylbenzene

• p-Xylene

• m-Xylene

• Mesitylene

• Durene

• 2-Phenylhexane

• Biphenyl

• Phenol

• Aniline

• Nitrobenzene

• Benzoic acid

• Aspirin

• Paracetamol

• Picric acid

The arene ring has an ability to stabilize charges. This is seen in, for example, phenol (C₆H₅-OH), which is acidic at the hydroxyl (OH), since a charge on this oxygen (alkoxide -O–) is partially delocalized into the benzene ring.