Naphtholphthalein
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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 | |
3D model (JSmol) | |
97816 | |
ChemSpider | |
ECHA InfoCard | 100.008.979 |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
| |
Properties | |
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)[1] |
Insoluble | |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards | Irritant |
GHS labelling: | |
[1] | |
Warning | |
H315, H319, H335[1] | |
P261, P305+P351+P338[1] | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
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 |
References[edit]
- ^ a b c d α-Naphtholphthalein