12-07393. Phenolphthalein Sodium [Archived]

Nomenclature

CAS number: 518-51-4
3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone disodium salt.
C20H12Na2O4; mol wt 362.29.
C 66.30%, H 3.34%, Na 12.69%, O 17.66%.

Description and references

Prepd from an alcoholic soln of 1 mol phenolphthalein by the addition of 2 mols NaOH. Structure: Buu-Hoi, Bull. Soc. Chim. [5] 8, 165 (1941).

Chemical structure

Properties

Reddish-brown granular mass with coppery luster, or pale red powder. Dec in air. Soluble in water, giving a deep-red soln. Absorption max: 550-555 nm. The unstable enol form is colorless, as is the trisodium salt.

Status

This monograph has been retired and is no longer subject to revision or update.