α-Naphtholbenzein (pH Indicator)

Name: α-Naphtholbenzein (pH Indicator)
Brand: Vaqora Chemicals
SKU: VQ-000741

About α-Naphtholbenzein (pH Indicator)

α-Naphtholbenzein (pH Indicator) is a biological stain carrying the CAS registry number 145-50-6. The compound has the formula C27H18O2, corresponding to a molecular weight of 374.4 g/mol. Systematically, it is named (4E)-4-[(4-hydroxynaphthalen-1-yl)-phenylmethylidene]naphthalen-1-one. It is also known as 4,4'-(a-Hydroxybenzylidene)di-1-naphthol or p-naphtholbenzein.

The material typically appears as a dark reddish brown powder. Literature values give a melting point of 230-235 °C and a density of 1.28 g/cm3. Store sealed in a dry, well-ventilated location away from incompatible materials. It carries the GHS signal word “Warning” with 3 hazard statements. Review the Safety Data Sheet before use.

It is commonly used for histology and cytology staining, microscopy, clinical laboratories and indicator for titrations. Buyers come mainly from academic and industrial research, diagnostics and biotechnology and textiles and dyeing.

Vaqora Chemicals supplies α-Naphtholbenzein (pH Indicator) in 5 g, 25 g, 100 g and 1 kg packs, each shipped with a Certificate of Analysis (COA), and exports worldwide.

Typical applications

Histology & cytology staining
Microscopy
Clinical laboratories
Indicator for titrations

Industries

Specifications & identifiers

Chemical identifiers
Product name	α-Naphtholbenzein (pH Indicator)
Catalogue No.	VQ-000741
CAS Number	145-50-6
IUPAC name	(4E)-4-[(4-hydroxynaphthalen-1-yl)-phenylmethylidene]naphthalen-1-one
Molecular formula	C₂₇H₁₈O₂
Molecular weight	374.4 g/mol
Exact mass	374.1307
HSN code	29145000
InChIKey	VDDWRTZCUJCDJM-SOYKGTTHSA-N
SMILES	C1=CC=C(C=C1)/C(=C\2/C=CC(=O)C3=CC=CC=C23)/C4=CC=C(C5=CC=CC=C54)O
PubChem CID	3033966

Physical properties
Physical form	Powder
Appearance	Dark reddish brown powder
Melting point	230-235 °C
Density	1.28 g/cm3
LogP (XLogP3)	6.6
H-bond donors / acceptors	1 / 2
TPSA	37.3 Å²
Synonyms	4,4'-(a-Hydroxybenzylidene)di-1-naphthol, p-naphtholbenzein, 1(4H)-Naphthalenone, 4-[(4-hydroxy-1-naphthalenyl)phenylmethylene]-, 1(4H)-Naphthalenone, 4-((4-hydroxy-1-naphthalenyl)phenylmethylene)-, alphaNaphtholbenzein, 4(alpha(4Hydroxy1naphthyl)benzylidene)naphthalen1(4H)one, 1(4H)Naphthalenone, 4(alpha(4hydroxy1naphthyl)benzylidene), 1(4H)Naphthalenone, 4((4hydroxy1naphthalenyl)phenylmethylene), 1(4H)Naphthalenone, 4(alpha(4hydroxy1naphthyl)benzylidene) (8CI), 1-Naphtholbenzein, 4-[(4-Hydroxy-1-naphthalenyl)phenylmethylene]-1(4H)-naphthalenone, Naphtholbenzein

Safety & hazard information (GHS)

Harmful / irritant

Signal word: Warning

Hazard statements

H315Causes skin irritation
H319Causes serious eye irritation
H335May cause respiratory irritation

Precautionary statements: P261, P264, P264 + P265, P271, P280, P302 + P352, P304 + P340, P305 + P351 + P338, P319, P321, P332 + P317, P337 + P317, P362 + P364, P403 + P233, P405, P501

Classification is indicative (aggregated GHS notifications) and may vary by grade and concentration. Always refer to the SDS supplied with your lot.

Documents

Safety Data Sheet (SDS)16-section GHS · on request Certificate of AnalysisTypical / batch COA · on request Specification sheetTDS / MOA · on request

Other grades of CAS 145-50-6

AR

α-Naphtholbenzein (pH Indicator), AR

CAS: 145-50-6
Formula: C₂₇H₁₈O₂
MW: 374.4 g/mol

VQ-045977

BP/USP/EP/Ph. Eur.

α-Naphtholbenzein (pH Indicator), BP/USP/EP/Ph. Eur.

CAS: 145-50-6
Formula: C₂₇H₁₈O₂
MW: 374.4 g/mol

VQ-047204

Frequently asked questions

What is the CAS number of α-Naphtholbenzein (pH Indicator)?

The CAS Registry Number of α-Naphtholbenzein (pH Indicator) is 145-50-6. It is also known as 4,4'-(a-Hydroxybenzylidene)di-1-naphthol, p-naphtholbenzein, 1(4H)-Naphthalenone, 4-[(4-hydroxy-1-naphthalenyl)phenylmethylene]-.

What is the molecular formula and molecular weight of α-Naphtholbenzein (pH Indicator)?

α-Naphtholbenzein (pH Indicator) has the molecular formula C27H18O2 and a molecular weight of 374.4 g/mol. Its IUPAC name is (4E)-4-[(4-hydroxynaphthalen-1-yl)-phenylmethylidene]naphthalen-1-one.

Which grade and pack sizes of α-Naphtholbenzein (pH Indicator) can I order?

We supply α-Naphtholbenzein (pH Indicator), in 5 g, 25 g, 100 g, 1 kg packs. Larger bulk quantities and custom packing are quoted on request.

Do you provide a COA and SDS with α-Naphtholbenzein (pH Indicator)?

Yes. Every lot of α-Naphtholbenzein (pH Indicator) is shipped with a batch-specific Certificate of Analysis, and a 16-section GHS Safety Data Sheet is provided with the quotation and the shipment.

Can α-Naphtholbenzein (pH Indicator) be shipped internationally?

Yes. α-Naphtholbenzein (pH Indicator) is classified as hazardous, so it is packed in UN-approved packaging and shipped as dangerous goods under IATA/IMDG rules. We export worldwide on EXW, FOB, CIF and DAP terms.