Phthalic acid is a benzenedicarboxylic acid cosisting of two carboxy groups at ortho positions. Phthalic acid appears as white crystals or fine white powder.
Phthalic acid (PA, PTA), also called as 1,2-benzenedicarboxylic acid is an aromatic carboxylic acid. It is the ortho form of the three phthalic acid isomers, the other two being isophthalic acid (meta form) and terephthalic acid (para form). PA is the starting material in the synthesis of plasticizers.