S P E C I F I C A T I O N S

alpha-NAPHTHOLBENZEIN

Synonyms:					4,4'-(a-Hydroxybenzylidene)di-1-naphthol; a,a-Bis(4-hydroxy-1-
						naphthyl)benzyl alcohol
						p-Naphtholbenzein

CAS No:					145-50-6

Chemical Formula:				C27H18O2

Formula Weight:				374.43

Appearance:					Dark Pink to Red to Red -Brown to Brown  Powder

Melting Point:				237 – 240° C 

Loss on Drying at 110° C			5% maximum
1 hour:

Maximum of Absorption:			644.0 - 656.0 nm
 (in 0.01 N NaOH)

Visual Transition Interval:		From pH 8.2 (Pinkish - Yellow)
						To      pH 10.0 (blue to blue-green)	

 		
Effective: 04/01/17