Phthalic acid is used mainly in the form of anhydride to produce other chemicals such as dyes, perfumes, saccharin, phthalates, and many other useful products. Plasticizers such as phthalic acid esters (phthalates) are used in a wide range of consumer goods, commodities, and construction materials.

Application

Phthalic acid is produced by the catalytic oxidation of naphthalene or ortho-xylene directly to phthalic anhydride and a subsequent hydrolysis of the anhydride. Phthalic acid was first obtained by French chemist Auguste Laurent in 1836 by oxidizing naphthalene tetrachloride.