Title: o-Cresolphthalein
CAS Registry Number: 596-27-0
CAS Name: 3,3-Bis(4-hydroxy-3-methylphenyl)-1(3H)-isobenzofuranone
Additional Names: 3,3¢-dimethylphenolphthalein
Molecular Formula: C22H18O4
Molecular Weight: 346.38
Percent Composition: C 76.28%, H 5.24%, O 18.48%
Literature References: Prepn: F. J. Welcher, Organic Analytical Reagents vol. 4 (Van Nostrand, New York, 1948) p 482; Hubacher et al., J. Am. Pharm. Assoc. 42, 23 (1953).
Properties: Crystals from alc, mp 223°. Slightly sol in water; sol in alcohol. pK 9.4.
Melting point: mp 223°
pKa: pK 9.4
Use: As indicator: pH range, 8.2 colorless, 9.8 red. Analytical reagent. |