Isophthalic acid
Isophthalic acid is an organic compound with the formula C6H42. This colorless solid is an isomer of phthalic acid and terephthalic acid. The main industrial uses of purified isophthalic acid are for the production of polyethylene terephthalate resin and for the production of unsaturated polyester resin and other types of coating resins.
Isophthalic acid is one of three isomers of benzenedicarboxylic acid, the others being phthalic acid and terephthalic acid.
Crystalline isophthalic acid is built up from molecules connected by hydrogen bonds, forming infinite chains.
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. The world's largest producer of isophthalic acid is Lotte Chemical Corporation.In the laboratory, chromic acid can be used as the oxidant. It also arises by fusing potassium meta-sulfobenzoate, or meta-bromobenzoate with potassium formate.
The barium salt, as its hexahydrate, is very soluble in water. Uvitic acid, 5-methylisophthalic acid, is obtained by oxidizing mesitylene or by condensing pyroracemic acid with baryta water.