Chemistry:Naphtholphthalein

Naphtholphthalein

Names
Preferred IUPAC name 3,3-Bis(4-hydroxynaphthalen-1-yl)-2-benzofuran-1(3H)-one
Other names 1-Naphtholphthalein, alpha-naphtholphthalein, naphtholphthalein blue
Identifiers
CAS Number	596-01-0 Y
3D model (JSmol)	Interactive image
Beilstein Reference	97816
ChemSpider	62215 N
PubChem CID	68993
UNII	2QEG1706NN Y
SMILES C1=CC=C2C(=C1)C(=CC=C2O)C3(C4=CC=CC=C4C(=O)O3)C5=CC=C(C6=CC=CC=C65)O
Properties
Chemical formula	C28H18O4
Molar mass	418.448 g·mol−1
Appearance	Colorless-reddish to blue-green solid
Melting point	238–240 °C (460–464 °F; 511–513 K)
Solubility in water	Insoluble
Hazards
Main hazards	Irritant
GHS pictograms
GHS Signal word	Warning
GHS hazard statements	H315, H319, H335
GHS precautionary statements	P261, P305+351+338
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Tracking categories (test):

• SizeSet

α-Naphtholphthalein (C₂₈H₁₈O₄) is a phthalein dye used as a pH indicator with a visual transition from colorless/reddish to greenish blue at pH 7.3–8.7.

Naphtholphthalein (pH indicator)
below pH 7.3		above pH 8.7
7.3	⇌	8.7