phthalic anhydride

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A white crystalline compound, C₈H₄C₃, the anhydride of phthalic acid, used in the manufacture of phthaleins and other dyes, resins, plasticizers, and insecticides.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun organic chemistry The acid anhydride of phthalic acid; manufactured by the oxidation of xylene or naphthalene, widely used in the synthesis of dyes, insecticides, plasticizers and pharmaceuticals.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a white cyclic anhydride