phthalinn.
/ˈ(f)θalɪn/, /ˈ(f)θeɪlɪn/, U.S. /ˈθeɪl(ə)n/ Chemistry.
Any of a series of typically colourless organic compounds resulting from the reduction of a phthalein, involving breaking of the heterocyclic ring by the addition of hydrogen; esp. = phenolphthalin n.
ΚΠ
1875 H. Watts Dict. Chem.: 2nd Suppl. 977 By the action of nascent hydrogen the phthaleins are converted into colourless compounds called phthalins, which by oxidation in the air, are reconverted into phthaleins.
1913 Jrnl. Amer. Chem. Soc. 35 1297 Tests have been made in this work using 1 cc. of guaiacum or phthalin and adding 10 cc. of sodium nitrite solution... No blue or red color was obtained at once, only a trace after 1 hour.
1940 Jrnl. Amer. Chem. Soc. 62 3191/1 Interaction with sulfuric acid converts the phthalin into 2,5-di-(p-hydroxyphenyl)-3,4-benzofuran.
This entry has been updated (OED Third Edition, March 2006; most recently modified version published online March 2022).
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