benzene13dicarboxylic

Benzene-1,3-dicarboxylic acid, commonly known as isophthalic acid, is an aromatic dicarboxylic acid. Its two carboxyl groups are attached to the benzene ring at the 1 and 3 positions, giving a meta arrangement. In its solid form it is a white crystalline substance that is sparingly soluble in water but dissolves in many organic solvents. It is usually handled and stored as a dry, stable solid under appropriate conditions.

Industrial production of isophthalic acid is dominated by catalytic oxidation of m-xylene (1,3-dimethylbenzene). Under controlled oxidation, the methyl groups are converted to carboxyl groups, yielding isophthalic acid after purification. The process is designed to minimize formation of other isomers such as terephthalic or trimellitic acids, which can arise as byproducts. Isophthalic acid is typically isolated as a solid salt or purified acid suitable for polymerization feedstocks.

Uses of isophthalic acid center on its role as a monomer or co-monomer in the production of polyesters and alkyd resins. When combined with glycols or other diols, it forms copolyesters that can exhibit improved chemical resistance, flexibility, or heat stability relative to base polymers. It is also a precursor to isophthalate esters used in coatings, adhesives, and specialty resins, and it serves as a building block for crosslinking agents and other specialty chemicals.

Safety and handling notes emphasize standard chemical hygiene: use in well-ventilated areas, protective clothing, and avoidance of inhalation or prolonged skin contact. It is generally regarded as an irritant, and proper storage and disposal practices are recommended in accordance with applicable regulations.