COA Center



1-NAPHTHOLBENZEIN Indicator grade

Used as an indicator 0.1g in 100 ml 2-propanol.
a-Naphtholbenzein; 4,4'-(a-Hydroxybenzylidene)di-1-naphthol; p-naphtholbenzein


5 g (00005)

25 g (00025)

1GBA000015 1GBA000060
Article No. 04765 Grade Indicator grade
Purity CAS No. 145-50-6
Molecular Formula C27H18O2 Molecular Weight 374.44
H.S. Code 2914.5000 Shelf Life 60 Months

Physical Properties

Physical state at 20 °C Solid Colour Dark reddish black
Odour Odorless Melting point/ Freezing point [°C] 185°C
Vapour density 12.9 Solubility in water [% weight] Insoluble in water


Appearance Dark red to red-brown to brown-black to orange-brown powder Visual transition interval pH 8.2 (yellow to orange) to pH 10 (green-blue)
Absorption maxima in acetic perchloric acid 0.1 mol/L 622 - 626 nm

Safety Information and Hazard Symbols

Exclamation Mark
Symbol: GHS07
Signal Word: Warning
Hazardous Statement: H315-H319-H335
Precaution Statement: P261-P305 + P351 + P338
Revision Date: 26-Oct-2020

Download MSDS & COA on your Mobile through LOBACHEMIE APP