Molekula
Naphthol Orange
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 2000 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Naphthol Orange is the sodium salt of a monoazo acid dye used in textile and pigment applications. Its main documented uses are dyeing textiles and leather, including printing and finishing work, and serving as an indicator dye in the laboratory. It is a bright orange powder with good lightfastness and stability. CAS: 523-44-4, Molecular Formula: C16H11N2NaO4S, Molecular Weight: 350.32. Stored at ambient temperature. No signal word applies. Molekula supplies Naphthol Orange from research to bulk quantities with full documentation and ISO 9001:2015 traceability.
Example image for illustration only. Other packaging and pack sizes are available.
Pricing & pack sizes
Pack sizes & pricing
Pricing on request — packs available from research to bulk quantities.
Need a different quantity or pack?
Tell us how much you need and when — drums, IBCs, sacks or a one-off bulk lot. We'll manufacture or source it and come back with a price.
Prices exclude VAT/sales tax and shipping.
Specifications
| Property | Value |
|---|---|
| Appearance | Orange to red powder |
| pH | 7.6 - 8.9 |
| Loss on Drying | ≤ 6.0% |
| Assay | ⩾ 85.0% |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
| Acidity | Neutral |
Literature values
Published physical properties of the substance, not batch specifications.
| Property | Value |
|---|---|
| Appearance | Reddish-brown powder |
Source: PubChem CID 135513128 (HSDB)
Identification
| Property | Value |
|---|---|
| SKU | 90034815 |
| CAS Number | 523-44-4 |
| IUPAC Name | sodium 4-[(4-hydroxynaphthalen-1-yl)diazenyl]benzenesulfonate |
| EC Number | 208-346-6 |
| Molecular Formula | C16H11N2NaO4S |
| Molecular Weight | 350.32 |
| Exact Mass | 350.0337 |
| SMILES | C1=CC=C2C(=C1)C(=CC=C2O)N=NC3=CC=C(C=C3)S(=O)(=O)[O-].[Na+] |
| InChIKey | AZLXCBPKSXFMET-UHFFFAOYSA-M |
| InChI | InChI=1S/C16H12N2O4S.Na/c19-16-10-9-15(13-3-1-2-4-14(13)16)18-17-11-5-7-12(8-6-11)23(20,21)22;/h1-10,19H,(H,20,21,22);/q;+1/p-1 |
| PubChem CID | 135513128 |
| REACH Code | Y113 |
| TSCA Listed | Yes |
| HTS Code | 2927005000 |
| Tariff Code | 2927000090 |
Safety & GHS
Precautionary statements
- P264 Wash thoroughly after handling
- P280 Wear protective gloves/protective clothing/eye protection/face protection
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, Portuguese, Spanish.
Certificate of Analysis (CoA) by batch
Enter a lot or batch number to retrieve the CoA for that specific batch. We can generate one from spec data if no PDF is on file.
Synonyms
- A.F. Orange No. 1
- Acid Leather Orange I
- Acid Orange 20
- alpha-Naphthol orange
- C.I. Acid Orange 20
- Japan Orange 1
- Orange I
- Sodium 4-((4-hydroxynaphthalen-1-yl)diazenyl)benzenesulfonate
- Tropaeolin 1
- Yellow 404
Frequently asked questions
What is Naphthol Orange used for?
Naphthol Orange (Orange I, C.I. Acid Orange 20) is a finished azo acid dye used directly to dye wool, silk, leather and paper, and it was formerly used as a colourant.
What is the chemical formula and molecular weight of Naphthol Orange?
The formula is C16H11N2NaO4S with a molecular weight of 350.32 g/mol.
How should Naphthol Orange be stored?
It should be stored at ambient temperature, protected from moisture and light.
What grade of Naphthol Orange is available?
Molekula offers Naphthol Orange in technical grade for industrial applications.
Can Molekula supply Naphthol Orange in bulk?
Yes, Molekula can supply Naphthol Orange in bulk quantities upon request.
What documentation comes with a purchase of Naphthol Orange?
Each order includes a Certificate of Analysis and Safety Data Sheet (SDS) with the shipment.
Ready to order or need a custom pack?
Tell us the product, grade, and quantity — Molekula usually responds within one working day with pricing and lead time.