| Preferred IUPAC name
| Other names
|3D model (Jmol)||Interactive image|
|Molar mass||166.14 g/mol|
|Appearance||White crystalline solid|
|Density||1.526 g/cm3, Solid|
|Insoluble in water|
|Acidity (pKa)||3.46, 4.46|
EU classification (DSD)
Related carboxylic acids
| Benzoic acid|
Phthalic acid (ortho)
Terephthalic acid (para)
Trimesic acid (benzene-1,3,5-tricarboxyllic acid)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|(what is ?)|
Isophthalic acid is produced on the billion kilogram per year scale by oxidizing meta-xylene using oxygen. 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.
Aromatic dicarboxylic acids are used as precursors (in form of acyl chlorides) to commercially important polymers, e.g. the fire-resistant material Nomex. Mixed with terephthalic acid, isophthalic acid is used in the production of resins for drink plastic bottles. The high-performance polymer polybenzimidazole is produced from isophthalic acid. Also, the acid is used as an important input to produce insulation materials.
- Brown, H.C., et al., in Baude, E.A. and Nachod, F.C., Determination of Organic Structures by Physical Methods, Academic Press, New York, 1955.
- Richard J. Sheehan "Terephthalic Acid, Dimethyl Terephthalate, and Isophthalic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.doi:10.1002/14356007.a26_193