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Merck
CN

291099

α-Naphtholbenzein

indicator grade

Synonym(s):

4,4′-(α-Hydroxybenzylidene)di-1-naphthol, p-naphtholbenzein

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About This Item

Empirical Formula (Hill Notation):
C27H18O2
CAS Number:
145-50-6
Molecular Weight:
374.43
NACRES:
NA.47
PubChem Substance ID:
24857510
UNSPSC Code:
12171500
EC Number:
205-656-3
Beilstein/REAXYS Number:
2628063

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InChI key

VDDWRTZCUJCDJM-PNHLSOANSA-N

InChI

1S/C27H18O2/c28-25-16-14-23(19-10-4-6-12-21(19)25)27(18-8-2-1-3-9-18)24-15-17-26(29)22-13-7-5-11-20(22)24/h1-17,28H/b27-24-

SMILES string

Oc1ccc(\C(c2ccccc2)=C3\C=CC(=O)c4ccccc34)c5ccccc15

grade

indicator grade

form

powder

technique(s)

titration: suitable

color

faintly Faint Brown to Very Dark Brown to Very Dark Red and Black

pH

0.0, green, 0.8, yellow, 10.0, blue-green, 8.2, yellow

mp

230-235 °C (lit.)

ε (extinction coefficient)

≥50000 at 207-213 nm in methanol at 0.01 g/L

application(s)

diagnostic assay manufacturing
hematology
histology

storage temp.

room temp

Quality Level

100

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General description

α-Naphtholbenzein is a dye belonging to the Benzein family insoluble in water and soluble in alcohol. α-Naphtholbenzein is primarily used as an indicator for pH range 8.2-10.0 (mostly in acid-base titrations), causing a color change for the neutral solutions turning alkaline. Its applications include detection of bacterial growth in packed food, viable cells, enzymes, ammonia odors in patients with bacterial infection, and many more.

Application

α-Naphtholbenzein has been used as an indicator during sequential injection analysis technique done for acid-base titrations.

hcodes

H413

Hazard Classifications

Aquatic Chronic 4

Storage Class

11 - Combustible Solids

wgk

WGK 2

flash_point_f

Not applicable

flash_point_c

Not applicable

ppe

dust mask type N95 (US), Eyeshields, Gloves

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Certificates of Analysis (COA)

Lot/Batch Number
SDBB4543
SDBB2878
STBL4373
STBL2433
STBK9325

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