Isophthalic acid

The oxidation of m-xylene produces isophthalic acid. The reaction occurs in the liquid-phase in presence of ammonium sulfite:

Isophthalic acid’s main use is for producing polyesters that are characterized by a higher abrasion resistance than those using other phthalic acids.

Polyesters from isophthalic acid are used for pressure molding applications. Ammoxidation of isophthalic acid produces isophthalonitrile. The reaction resembles the one used for ammoxidation of phthalic anhydride:

Isophthalonitrile serves as a precursor for agricultural chemicals. It is readily hydrogenated to the corresponding diamine, which can form polyamides or be converted to isocyanates for polyurethanes.