Naphtholphthalein
Names | |
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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 |
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3D model (JSmol) |
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Beilstein Reference | 97816 |
ChemSpider |
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ECHA InfoCard | 100.008.979 |
PubChem CID |
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UNII |
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CompTox Dashboard (EPA) |
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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)[1] |
Solubility in water | Insoluble |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards | Irritant |
GHS labelling: | |
Pictograms | [1] |
Warning | |
Hazard statements | H315, H319, H335[1] |
Precautionary statements | 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). N verify (what is YN ?) Infobox references |
Chemical compound
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
- ^ a b c d α-Naphtholphthalein
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