Isophtalic acid (PIA)

An organic chemical compound being an aromatic acid containing two carboxyl groups in the meta position. Its orto isomer is the phthalic acid, while the para isomer is the terephthalic acid.
It is a white crystal with poor water, alcohol and acetic acid solubility (benzene-insoluble).

Method of obtaining:

It is obtained by oxygenating metaxylene with chromic acid or through the fusion of potassium with meta-sulphobenzoate or meta-brombenzoate with potassium formate.


PIA has excellent application properties, including excellent hardness and corrosion resistance. Polyesters containing the isophthalic acid are also widely used in industrial coatings for household appliances, vehicles, metal and office furniture. It is also used as an intermediate compound for polyesters, polyurethane resins and plastifiers.

Storage and transport

Store tightly sealed containers in a cool, dry and well-ventilated place.

Chemical formula: C8 H6 O4
Density: 1.451 g/cm3
CAS: 121-91-5