Definition - What does Phthalic Anhydride mean?
Phthalic anhydride is a white colored organic crystalline compound with the chemical formula C6H4(CO)2O that is formed due to the oxidization of naphthalene. It reacts exothermically when in contact with water and as such can accelerate corrosion.
Corrosionpedia explains Phthalic Anhydride
Phthalic anhydride is used to manufacture materials such as artificial resins. It is the commercially used form of phthalic acid. Phthalic anhydride is usually used as a chemical median for the production of plastics from vinyl chloride. It is known as an adaptable intermediate in chemical processes because it is bifunctional and readily available.