Title: Phenolphthalein Sodium

CAS Registry Number: 518-51-4

CAS Name: 3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone disodium salt

Molecular Formula: C20H12Na2O4

Molecular Weight: 362.29

Percent Composition: C 66.30%, H 3.34%, Na 12.69%, O 17.66%

Literature 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).

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.

Absorption maximum: Absorption max: 550-555 nm

 

 

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