Chemistry:Benzene polycarboxylic acid

A benzene polycarboxylic acid is a derivative of benzene with two or more carboxylic acid functional groups. These compounds have the chemical formula C
6+nH
6O
2n or C
6H
6-n(COOH)
n.

• Benzenedicarboxylic acid, $n=2$, three isomers:
  • Isophthalic acid (1,2-benzenedicarboxylic acid)
  • Phthalic acid (1,3-benzenedicarboxylic acid)
  • Terephthalic acid (1,4-benzenedicarboxylic acid)
• Benzenetricarboxylic acid, $n=3$, three isomers:
  • Hemimellitic acid (1,2,3-benzenetricarboxylic acid)
  • Trimellitic acid (1,2,4-benzenetricarboxylic acid)
  • Trimesic acid (1,3,5-benzenetricarboxylic acid)
• Benzenetetracarboxylic acid, $n=4$, three isomers:
  • 1,2,3,4-benzenetetracarboxylic acid
  • 1,2,3,5-benzenetetracarboxylic acid
  • Pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid)
• Benzenepentacarboxylic acid, $n=5$
• Mellitic acid (benzenehexacarboxylic acid), $n=6$