Formula C6H4(COOH)2 Density 1.53 g/cm³ | Molar mass 166.14 g/mol Appearance White crystalline solid | |
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Isophthalic acid is an organic compound with the formula C6H4(CO2H)2. This colourless solid is an isomer of phthalic acid and terephthalic acid.
Contents
Preparation
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.
Applications
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.