| Identification | More | [Name]
Direct Red 28 | [CAS]
573-58-0 | [Synonyms]
3,3'-[(1,1'-BIPHENYL)-4,4'-DIYLBIS(AZO)]BIS(4-AMINO-1-NAPHTHALENESULFONIC ACID) 2NA
CI 22120
CI NO 22120
CONGO
CONGO RED
CONGO RED 4B
CONGO RED FIBRIN
CONGO RED INDICATOR
CONGO RED TS
COSMOS RED
COTTON RED
COTTON RED B OR C
DIRECT RED
DIRECT RED 28
DIRECT RED C, R, OR Y
Disodium 3,3'-[[1,1'-biphenyl]-4,4'-diylbis(azo)]bis(4-aminonaphthalene-1-sulphonate)
ERIE CONGO 4B
S NO 360
1-naphthalenesulfonicacid,3,3’-((1,1’-biphenyl)-4,4’-diylbis(azo))bis(4-amino
1-naphthalenesulfonicacid,3,3’-[[1,1’-biphenyl]-4,4’-diylbis(azo)]bis[4-amino | [EINECS(EC#)]
209-358-4 | [Molecular Formula]
C32H22N6Na2O6S2 | [MDL Number]
MFCD00004028 | [Molecular Weight]
696.66 | [MOL File]
573-58-0.mol |
| Chemical Properties | Back Directory | [Appearance]
C.I. Direct red 28(Congo Red) is an odorless, brownish-red powder. | [Melting point ]
>360 °C (lit.) | [density ]
0.995 g/mL at 25 °C | [vapor pressure ]
<1 Pa | [storage temp. ]
Flammables area | [solubility ]
H2O: soluble10mg/mL | [Colour Index ]
22120 | [form ]
Powder/Solid | [pka]
4.1(at 25℃) | [color ]
Red Brown | [Odor]
Odorless | [PH]
6.7 (10g/l, H2O, 20℃) | [PH Range]
3(blue)-5.2(red) | [Stability:]
Stable. Incompatible with strong oxidizing agents. | [Water Solubility ]
soluble | [λmax]
497nm, 488nm, 595nm | [Merck ]
14,2498 | [BRN ]
3894858 | [Biological Applications]
Detecting bacteria,protein folding disorders; treating dermatological disorders,neurodegenerative diseases,Alzheimer’s disease | [Major Application]
Waveguides, optical sensors, display devices, inks, fertilizer, pesticides, carbohydrates, treatment of pathogen infections, age-related macular degeneration | [Uses]
Dye, medicine (diagnostic aid), indicator, biological stain. | [CAS DataBase Reference]
573-58-0(CAS DataBase Reference) | [EPA Substance Registry System]
573-58-0(EPA Substance) |
| Safety Data | Back Directory | [Hazard Codes ]
T,Xi | [Risk Statements ]
R45:May cause cancer.
R63:Possible risk of harm to the unborn child.
R36:Irritating to the eyes. | [Safety Statements ]
S53:Avoid exposure-obtain special instruction before use .
S45:In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) .
S37/39:Wear suitable gloves and eye/face protection .
S26:In case of contact with eyes, rinse immediately with plenty of water and seek medical advice . | [WGK Germany ]
3
| [RTECS ]
QK1400000
| [TSCA ]
Yes | [HS Code ]
29215900 | [Safety Profile]
Human poison by ingestion with cardovascular effects. Experimental poison by intravenous route. An experimental teratogen. Experimental reproductive effects. An eye irritant. Mutation data reported. When heated to decomposition it emits very toxic fumes of NOx, SOx, and Na2O | [Hazardous Substances Data]
573-58-0(Hazardous Substances Data) | [Toxicity]
LD50 i.v. in rats: 190 mg/kg (Richardson, Dillon) |
| Hazard Information | Back Directory | [Potential Exposure]
It is used as an indicator dye, a biological stain; a diagnostic aid in medicine; and a dye for fabric and paper. | [First aid]
If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. If victim is conscious, administer water or milk. Do not induce vomiting | [Shipping]
UN3143 Dyes, solid, toxic, n.o.s. or Dye intermediates, solid, toxic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required | [Incompatibilities]
Contact with oxidizers may cause fire and explosion hazard. Incompatible with strong acids; reducing agents. | [Description]
C.I. Direct red 28(Congo Red) is an odorless,brownish-red powder. Molecular weight =698.72. Meltingpoint =359℃. Soluble in water; solubility =25 g/L at25℃. | [Definition]
ChEBI: An indicator dye that is blue-violet at pH 3.0 and red at pH 5.0. | [Biochem/physiol Actions]
Congo red is a benzidine-based anionic diazo dye. It is a histological dye which binds to many amyloid proteins and is used for the quantification of amyloid β-peptide aggregation. Congo red also interacts with β-D-glucans, polysaccharides containing continuous β-(1→4)-linked D-glucopyranosyl units and some hemicellulosic galactoglucomannans. | [storage]
Store at 4°C, protect from light | [Properties and Applications]
|
Standard
|
Acid Resistance
|
Alkali Resistance
|
Light Fastness
|
Soaping
|
Water
|
|
Fading
|
Stain
|
Fading
|
Stain
|
|
ISO
|
1
|
3
|
1
|
2
|
|
2
|
|
|
AATCC
|
1
|
3
|
2
|
1
|
|
3
|
|
| [Purification Methods]
Crystallise the dye from aqueous EtOH (1:3). Dry it in air. [Beilstein 6 I 342.] |
| Questions And Answer | Back Directory | [Artificial dyes]
Congo red is aniline dye or coal tar dyes, and it has many types with very wide application. Its drawback is easy to fade by sunlight; aniline blue, bright green, methyl green are more easily fade. Be careful to handle the pH, and avoid direct sunlight when flaking, thus it will keep a few years without fading.
Congo red is an acid dye, a purplish red powder. It is soluble in water and alcohol, turning blue when in acid. It can be used as a dye as well as an indicator. In the production of plant slide, it is often used as a liner agent for hematoxylin or other cell dyes. When used in cytoplasm dyes, it can dye the cytosol or fibrin red. In the process of tissue slicing, it is used to dye nerve axis, elastic fibers, embryonic materials, etc. In addition, Congo red can be used for double staining with hematoxylin; it can also be used for amyloid staining. For it is soluble in water and alcohol, so washing and dehydration treatment should be quick. | [Chemical properties]
Congo red is red-brown powder, soluble in hot water and the cold water 10 times of its weight; the color of the solution is yellow-red; soluble in ethanol and the solution is orange; slightly soluble in acetone, while almost insoluble in ether. The solution is dark blue when in sulfuric acid, turning to light blue accompanied with the appearance of blue precipitate when diluted.
Its aqueous solution will form a blue floc when in concentrated hydrochloric acid. When added with acetic acid, the precipitate turned blue with a little purple to a precipitate with some red color. It is insoluble in the concentration of caustic soda solution; susceptible to acid and salt which means even if its absorption of carbon dioxide from the air will make the color blue and dark, while dilute soda solution can restore the original color.
Information on the chemical properties, uses and production methods of artificial dyes Congo Red is compiled and edited by Chemcialbook. | [Uses]
1. It has been widely used in cotton, viscose dyeing. Because it can easily be transformed into blue when in acid, while there is no appropriate treatment to improve, the usage amount is gradually decreased since the advent of insoluble azo dyes and acid-resistant red 4BS, however, the amount used in the paper industry is quite large. It can also be used as indicators of acid-base, namely Congo red test paper. The measurable range pH is 3.0 (blue)-5.0 (red). It is also used for biological staining, analysis reagents.
2. An indicator frequently used in lab as well as a carcinogenic disperse dyes; used to standard test.
3. Used as an acid-base indicator, adsorption indicator and biological stain, etc.
4. Acid-base indicator, pH 3.0 (blue violet)~5.0 (red); detect the acidity of paper and hydrochloric acid in the gastric juice; test boric acid, cyanide; biological media additives; biological staining, such as embryo slices, plant mucin, cellulose, elastic tissue dyeing.
5. Mainly used for dyeing cotton, hemp, silk and other textile and paper products; it can also be used as an indicator. | [Production methods]
It is obtained by the coupling with sodium naphthionate after the diazotization with benzidine, and then by salting out, filtration and drying in the system. The details are as follows: add 48.4 benzidine into 300ml of hydrochloric acid take 48.4g benzidine dissolved in 300ml hydrochloric acid (including 20ml of concentrated hydrochloric acid 20ml), add ice into the solution until the temperature is below 5 ℃; add 10% aqueous solutions prepared by 14.4g sodium nitrite after adding 30ml of concentrated hydrochloric acid.Add the diazonium salt solution slowly into the solution prepared by 150g sodium naphthionate and a little water after diazotization. Add 35g sodium carbonate slowly under the sufficient mixing after 30 minutes' standing, thus appearing an alkaline solution. Heating to 80℃, cooling, filtering, washing with saturated brine and drying can obtain the product. The materials consumption (kg/t) in industrial production are as follows: benzidine (100%) 200, sodium naphthionate (100%) 520, sodium nitrite (industry) 160, hydrochloric acid (31%) 330, soda ash (industrial) 340, fine salt 2500, turkey red oil 9, ethanol 60, sodium acetate 35, sodium sulfate 50. |
|
|