Molekula
Chromotrope 2B
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
Chromotrope 2B is the disodium salt of a monoazo dye, in which a 4-nitrophenylazo group is attached to a chromotropic acid (4,5-dihydroxynaphthalene-2,7-disulfonic acid) core, used as a pH indicator and in dyeing textiles and paper. It appears as a dark red crystalline powder. CAS: 548-80-1, Molecular Formula: C16H9N3O10S2·2Na, Molecular Weight: 513.37 g/mol. Store at ambient temperature. Warning signal word applies. Molekula supplies Chromotrope 2B 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
These pack sizes aren't a limit. Molekula manufactures, sources and repacks to order — if you need 500 kg and only see 1 kg listed, . We quote from grams to multi-tonne.
Need a different size? Add the nearest pack and change the size in your basket — we price it at the same rate per unit.
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25 g — £46.70 per pack ex VAT · £56.04 inc. VAT
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 | Brown red to red powder |
| Sensitivity test for boron | Passes test |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
Identification
| Property | Value |
|---|---|
| SKU | 70226119 |
| CAS Number | 548-80-1 |
| IUPAC Name | disodium;4,5-dihydroxy-3-[(4-nitrophenyl)diazenyl]naphthalene-2,7-disulfonate |
| EC Number | 208-959-9 |
| Molecular Formula | C16H9N3O10S2·2Na |
| Molecular Weight | 513.37 |
| Exact Mass | 512.9525 |
| SMILES | C1=CC(=CC=C1N=NC2=C(C3=C(C=C(C=C3C=C2S(=O)(=O)[O-])S(=O)(=O)[O-])O)O)[N+](=O)[O-].[Na+].[Na+] |
| InChIKey | AXUUHWJXDWBCSG-UHFFFAOYSA-L |
| InChI | InChI=1S/C16H11N3O10S2.2Na/c20-12-7-11(30(24,25)26)5-8-6-13(31(27,28)29)15(16(21)14(8)12)18-17-9-1-3-10(4-2-9)19(22)23;;/h1-7,20-21H,(H,24,25,26)(H,27,28,29);;/q;2*+1/p-2 |
| PubChem CID | 68360 |
| REACH Code | Y110 |
| TSCA Listed | Yes |
| HTS Code | 29270050 |
| Tariff Code | 2927000090 |
Safety & GHS
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Health Hazard
GHS07
Hazard statements
- H315 Causes skin irritation
- H319 Causes serious eye irritation
- H335 May cause respiratory irritation
Precautionary statements
- P261 Avoid breathing dust/fume/gas/mist/vapours/spray
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P302+352 IF ON SKIN: Wash with soap and water
- P304+340 IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing
- P305+351+338 IF IN EYES: Rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, 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
- 4,5-DIHYDROXYNAPHTHALENE-3-(4-NITROPHENYLAZO)-2,7-DISULFONIC ACID DISODIUM SALT
- C.I. 16575
- C.I. Acid Red 176
- C.I. Acid Red 176, disodium salt
- Chromotrope Red 4B
- CR-2B
- Khromotrop 2B
- Naphtocard Fast Red 3B
- p-Nitrobenzeneazochromotropic acid sodium salt
- PCR 2B
Frequently asked questions
What is Chromotrope 2B used for?
Chromotrope 2B is primarily used as a dye in textile and leather coloring, offering strong color fastness and bright hues.
What is the chemical formula and molecular weight of Chromotrope 2B?
The formula is C16H9N3O10S2·2Na with a molecular weight of 513.37 g/mol.
How should Chromotrope 2B be stored?
It should be stored at ambient temperature, away from moisture and direct sunlight.
What grade of Chromotrope 2B is available?
Molekula supplies Chromotrope 2B in technical grade for industrial applications.
Can Molekula supply Chromotrope 2B in bulk?
Yes, Molekula can supply Chromotrope 2B in bulk quantities; please contact sales for pricing and availability.
What documentation comes with a Chromotrope 2B order?
Each order includes a Certificate of Analysis and Safety Data Sheet (SDS) compliant with GHS standards.
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.