Congo red
From Sciencemadness Wiki
| Names | |
|---|---|
| IUPAC name
Disodium 4-amino-3-[4-[4-(1-amino-4-sulfonato-naphthalen-2-yl)diazenylphenyl]phenyl]diazenyl-naphthalene-1-sulfonate
| |
| Other names
1-Naphthalene sulfonic acid 3,3'-(4,4'-biphenylenebis(azo))bis(4-amino) disodium salt
Benzidinediazobis- 1-naphtylamine-4-sulfonic acid disodium salt C.I. Direct Red 28 Congo Red 4B Congorot Direct Red 28 Sodium diphenyldiazo-bis-a-naphthylaminesulfonate | |
| Properties | |
| C32H22N6O6S2Na2 | |
| Molar mass | 696.665 g/mol |
| Appearance | Red to red-brown solid |
| Melting point | 360 °C (680 °F; 633 K) |
| Boiling point | Decomposes |
| 11.6 g/100 ml (20 °C)[1] | |
| Solubility | Soluble in ethanol Almost insoluble in acetone Insoluble in diethyl ether |
| Vapor pressure | ~0 mmHg |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose)
|
190 mg/kg (rat, IV) |
| Related compounds | |
| Related compounds
|
Methyl red |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Congo red is an organic compound, an azo dye used in histology.
Contents
Properties
Chemical
Due to a color change from blue to red at pH 3.0–5.2, Congo red can be used as a pH indicator.
Physical
Congo red is a reddish or reddish-brown solid, soluble in water.
Availability
Congo red can be bought from chemical suppliers.
Preparation
Congo red can be synthesized by azo coupling of benzidine HCl and sodium napthionate.[2]
Projects
- Azo dye
- pH indicator
- Histological stain
- Detecting and estimating free HCl in gastric contents
Handling
Safety
Congo red is irritant and there is evidence to suggest it may cause cancer.
Storage
In closed bottles, away from light and air.
Disposal
Can be destroyed with a strong oxidizing solution.
References
- ↑ Solubility Handbook. - T.1, Book.1. - M.-L.: IAN USSR, 1961 (Справочник по растворимости. - Т.1, Кн.1. - М.-Л.: ИАН СССР, 1961)
- ↑ Shabir, Ghulam; Saeed, Aamer; Journal of the Chemical Society of Pakistan; vol. 39; nb. 1; (2017); p. 50 - 58
