Isophthalic acid

Isophthalic acid
Other names	Benzene-1,3-dicarboxylic acid meta-Phthalic acid
Identifiers
CAS number	121-91-5 Y
SMILES	C1=CC(=CC(=C1)C(=O)O)C(=O)O
Properties
Molecular formula	C6H4(COOH)2
Molar mass	166.14 g/mol
Appearance	White crystalline solid
Density	1.526 g/cm3, Solid
Solubility in water	Insoluble in water
Hazards
EU classification	not listed
Related compounds
Related carboxylic acids	Phthalic acid Terephthalic acid Benzoic acid
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Isophthalic acid is an organic compound with the formula C₆H₄(CO₂H)₂. This colourless solid is an isomer of phthalic acid and terephthalic acid. These aromatic dicarboxylic acids are used as precursors to polymers and other compounds of commercial significance. Mixed with terephthalic acid, isophthalic acid is used in the production of resins for drink bottles. The high-performance polymer polybenzimidazole is produced from isophthalic acid.^[1]

Preparation

Isophthalic acid is produced on the billion kilogram/y scale by oxidizing meta-xylene using oxygen.^[1] The process employs a cobalt-manganese catalyst. In the laboratory, chromic acid can be used as the oxidant. It also arises by fusing potassium meta-sulphobenzoate, or meta-brombenzoate with potassium formate (terephthalic acid is also formed in the last case).

The barium salt (as its hexahydrate) is very soluble (a distinction between phthalic and terephthalic acids). Uvitic acid, 5-methylisophthalic acid, is obtained by oxidizing mesitylene or by condensing pyroracemic acid with baryta water.

References

1. ^ ^{a b} Richard J. Sheehan "Terephthalic Acid, Dimethyl Terephthalate, and Isophthalic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.

External links

• International Chemical Safety Card 0500