Defn: Pertaining to, or designating, a dibasic acid obtained by the oxidation of naphthalene and allied substances. Phthalic acid (Chem.), a white crystalline substance, C6H4.(CO2H)2, analogous to benzoic acid, and employed in the brilliant dyestuffs called the phthaleins.
PHTHALIDE
Phthal"ide, n. Etym: [Phthalyl + anhydride.] (Chem.)
Defn: A lactone obtained by reduction of phthalyl chloride, as a white crystalline substance; hence, by extension, any one of the series of which phthalide proper is the type. [Written also phthalid.]
PHTHALIMIDE
Phthal"i*mide, n. Etym: [Phthalic + imide.] (Chem.)
Defn: An imido derivative of phthalic acid, obtained as a white crystalline substance, C6H4.(CO)2NH, which has itself (like succinimide) acid properties, and forms a series of salts. Cf. Imido acid, under Imido.
PHTHALIN
Phthal"in, n. (Chem.)
Defn: A colorless crystalline substance obtained by reduction from phthaleïn, into which it is easily converted by oxidation; hence, any one of the series of which phthalin proper is the type.
PHTHALYL
Phthal"yl, n. Etym: [Phthalic + -yl.] (Chem.)
Defn: The hypothetical radical of phthalic acid.
PHTHIRIASIS
Phthi*ri"a*sis, n. Etym: [L., fr. Gr. (Med.)