Title: Phenolphthalin
CAS Registry Number: 81-90-3
CAS Name: 2-[Bis(4-hydroxyphenyl)methyl]benzoic acid
Additional Names: decolorized phenolphthalein; phthalin; 4¢,4¢¢-dihydroxytriphenylmethane-2-carboxylic acid
Molecular Formula: C20H16O4
Molecular Weight: 320.34
Percent Composition: C 74.99%, H 5.03%, O 19.98%
Literature References: Made by boiling phenolphthalein with zinc dust in alkaline soln. Called "Kastle-Meyer reagent" when in soln. Prepd by dissolving 2 g phenolphthalin + 20 g KOH in a desired amt of doubly distd H2O and diluting with an equal vol of 95% ethanol. Detailed directions for prepn of test soln and its use: Lecoq, Bull. Soc. Chim. Belg. 54, 186-202 (1945), C.A. 41, 2346i (1947).
Properties: Colorless crystals, mp 237°. Insol in water; sol in alcohol, ether, aq alkali. The alkaline solns gradually become pink on exposure to air or other oxidizing substances.
Melting point: mp 237°
Use: As a reagent for oxidases, blood, HCN, peroxides, copper. |