Definition of phthalic anhydride in English:

phthalic anhydride


mass nounChemistry
  • A crystalline compound made by oxidizing naphthalene, used as an intermediate in the manufacture of plastics, resins, and dyes.

    A bicyclic anhydride; chemical formula: C₆H₄(CO)₂O

    • ‘Succinic anhydride has almost the same rate constant as acetic, while maleic anhydride reacts 10 times as quickly and phthalic anhydride four times.’
    • ‘Officials from China's Ministry of Foreign Trade and Economic Cooperation announced the measure targeting imports of phthalic anhydride to see whether they are sold at unfairly low prices and damaging local industries.’
    • ‘Alkyd resins are produced by the curing reaction of a material like phthalic anhydride with glycerol in the presence of a fatty acid.’
    • ‘This fraction is most typically drawn from the lighter fractions such as ethylene which is used for making polyethylene plastic while the preformed aromatic rings in the heavier fractions find use in such products as phthalic anhydride.’
    • ‘In one method, naphthalene is oxidized with vanadium pentoxide to give phthalic anhydride.’


Mid 19th century: phthalic, shortening of naphthalic (see naphthalene).