Name | Congo Red |
Synonyms | S NO 360 Congo Red Congo red C.I. 22120 Congo Red K Direct Red 28 Congo Ared 4b Direct Red 28 CONGO RED (CERT) Direct Scarlet 4B C.I. Direct Red 28 C.I. Direct Red 28, disodium salt C.I. Direct Red 28, disodium salt (8CI) 3,3'-[(1,1'-BIPHENYL)-4,4'-DIYLBIS(AZO)]BIS(4-AMINO-1-NAPHTHALENESULFONIC ACID) 2NA 3,3'-[(Biphenyl-4,4'-diyl)bisazo]bis(4-amino-1-naphthalenesulfonic acid sodium) salt disodium 3,3'-[biphenyl-4,4'-diyldi(E)diazene-2,1-diyl]bis(4-aminonaphthalene-1-sulfonate) 3,3'-[[1,1'-Biphenyl]-4,4'-diylbis(azo)]bis[4-amino-1-naphthalenesulfonic acid sodium] salt disodium 4-amino-3-[4-[4-[(1-amino-4-sulfonato-2-naphthyl)azo]phenyl]phenyl]azo-naphthalene-1-sulfonate |
CAS | 573-58-0 |
EINECS | 209-358-4 |
InChI | InChI=1/C32H24N6O6S2.2Na/c33-31-25-7-3-1-5-23(25)29(45(39,40)41)17-27(31)37-35-21-13-9-19(10-14-21)20-11-15-22(16-12-20)36-38-28-18-30(46(42,43)44)24-6-2-4-8-26(24)32(28)34;;/h1-18H,33-34H2,(H,39,40,41)(H,42,43,44);;/q;2*+1/p-2/b37-35-,38-36-; |
Molecular Formula | C32H22N6Na2O6S2 |
Molar Mass | 696.66 |
Density | 0.995g/mLat 25°C |
Melting Point | >360 °C (lit.) |
Water Solubility | soluble |
Solubility | Soluble in water is yellow-red, soluble in ethanol is orange, very slightly soluble in acetone, almost insoluble in ether |
Vapor Presure | <1 Pa |
Appearance | Brown powder |
Color | Red Brown |
Odor | Odorless |
Maximum wavelength(λmax) | ['497nm, 488nm, 595nm'] |
Merck | 14,2498 |
BRN | 3894858 |
pKa | 4.1(at 25℃) |
PH | 6.7 (10g/l, H2O, 20℃) |
Storage Condition | Store at +5°C to +30°C. |
Stability | Stable. Incompatible with strong oxidizing agents. |
Sensitive | Easily absorbing moisture |
MDL | MFCD00004028 |
Physical and Chemical Properties | Brown red powder, soluble in hot water, soluble in 10 cold water, the solution is yellow red; Soluble in ethanol Orange; Very slightly soluble in acetone, almost insoluble in ether. Soluble in ethanol orange, slightly soluble in acetone. Dark blue in concentrated sulfuric acid, diluted in light blue with blue against the precipitate. The aqueous solution with concentrated hydrochloric acid to produce blue blue precipitate; Acetic acid to produce blue purple to red blue precipitate. Not dissolved in concentrated caustic soda. Sensitive to acid and salt, even if carbon dioxide is absorbed from the air, the color will turn blue and dark, but the original color can be restored by treatment with dilute soda ash. |
Use | Used as acid-base indicator, adsorption indicator and biological stain |
Risk Codes | R45 - May cause cancer R63 - Possible risk of harm to the unborn child R36 - Irritating to the eyes |
Safety Description | S53 - Avoid exposure - obtain special instructions before use. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever 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 |
Toxicity | LD50 i.v. in rats: 190 mg/kg (Richardson, Dillon) |
Reference Show more | 1. Wu, Di, Xue, Wang, Chang, Tao, et al. Extraction of oat β-glucan by bidirectional fermentation and its physicochemical properties [J]. Food Research and development 2019 040(001):184-193. 2. Qi Wei, Zhou Shoulong, Gao xuili, etc. Construction of salmonella HPI gene deletion strain and its effect on phagocytosis of chicken macrophages [J]. Chinese poultry, 2016, 38(16). 3. Liu Xu, Zhou Wennan, Chen Zhao, et al. Effects of growth-promoting rhizobacteria on aging seed germination and seedling growth of Brome [J]. Heilongjiang Journal of Animal Husbandry and Veterinary Medicine, 2018, 000(011):24-31. 4. Yang Gang, Yang diqin, Cao Wentao, Wang Xiaodan. Optimization of cellulose-degrading bacteria and degradation process of distiller's grains [J]. Journal of Agricultural Engineering, 2020,36(13): 21-221. 5. Chen Lin, Wen Jiaxin, Lei Yi, et al. Simultaneous and rapid determination of 20 illegally added synthetic pigments in cured meat products by high performance liquid chromatography [J]. Chinese Journal of analysis and testing, 2015, 034(009):1008-1013. 6. Li, Rui, et al. "Isolation, physical, structural characterization and in vitro prebiotic activity of a galactomannan extracted from endosperm splits of Chinese Sesbania cannabina seeds." International journal of biological macromolecules 162 (2020): 1217-1 7. [IF=13.273] Qinzhi Wang et al."Magnetic amino-functionalized-MOF(M = Fe, Ti, Zr)@COFs with superior biocompatibility: Performance and mechanism on adsorption of azo dyes in soft drinks."Chem Eng J. 2021 Sep;420:129955 8. [IF=6.953] Rui Li et al."Isolation, physical, structural characterization and in vitro prebiotic activity of a galactomannan extracted from endosperm splits of Chinese Sesbania cannabina seeds."Int J Biol Macromol. 2020 Nov;162:1217 9. [IF=4.539] Xixi Piao et al."Improved properties of bamboo by thermal treatment with wood wax oil."Colloid Surface A. 2022 Jun;643:128807 10. [IF=6.953] Yiming Chen et al."Lightweight and anisotropic cellulose nanofibril/rectorite composite sponges for efficient dye adsorption and selective separation."Int J Biol Macromol. 2022 May;207:130 11. [IF=9.229] Miaomiao Han et al."Amyloid Protein-Biofunctionalized Polydopamine Nanoparticles Demonstrate Minimal Plasma Protein Fouling and Efficient Photothermal Therapy."Acs Appl Mater Inter. 2022;XXXX(XXX):XXX-XXX 12. [IF=15.881] Yiming Chen et al."Liquid Transport and Real-Time Dye Purification via Lotus Petiole-Inspired Long-Range-Ordered Anisotropic Cellulose Nanofibril Aerogels."Acs Nano. 2021;XXXX(XXX):XXX-XXX |
Color index | 22120 |
pH range of acid-base indicator discoloration | 3(blue)-5.2(red) |
Biological applications | Detecting bacteria,protein folding disorders, alzheimer's disease |
Main applications | waves, optical sensors, display devices, age-related macro generation |
EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
artificial dyes | that is aniline dyes or coal tar dyes, many kinds, a wide range of applications. Its disadvantage is that it is easy to fade by sunlight, aniline blue, bright green, methyl green and so on. In the production of attention to grasp the pH, and to avoid direct sunlight, but also after several years does not fade. Congo red (Congo red) is an acid dye, jujube red powder, soluble in water and alcohol, acid blue. Can be used as a dye, also used as an indicator. Often used as a liner for hematoxylin or other cellular dyes in plant preparations. When used to stain the cell mass, the glue or cellulose can be stained red. In animal tissue production used to stain the nerve axis, elastic fibers, embryonic material, etc. In addition, Congo red can be double dyed with hematoxylin static, can also be used as a kind of starch dyeing, because it can dissolve in water and alcohol, so the washing and dehydration treatment should be rapid. |
Use | has been widely used in cotton, viscose dyeing, because of its easy to change into blue, and no appropriate treatment methods to improve its wet treatment fastness, so since the insoluble azo dye and direct acid red 4BS came out, the use of the product in the dyeing is reduced, but in the paper industry, the use is quite large. It can also be used as an acid-base indicator, namely Congo red test paper, pH3.0 (blue violet)-5.0 (red). Also used for biological staining, analysis of reagents. mainly used for cotton, hemp, silk and other textile and paper products dyeing, can also be used as indicators laboratory indicators commonly used, but also a carcinogenic disperse dyes, for the detection of standards. used as acid-base indicator, adsorption indicator and biological stain, etc. Acid-base indicator, pH 3.0 (blue violet) ~ 5.0 (red); Hydrochloric acid in gastric juice and acidity of paper were detected; verification of boric acid, cyanide; Additives of biological medium; Biological staining, such as embryo slices, plant mucin, cellulose, elastic tissue staining acid-base indicator [pH3.0 (Blue Purple)] -5.0 (red)], adsorption indicator, precipitation of protein, detection of Free hydrochloric acid in gastric juice, embryo slices, plant mucin, cellulose, elastic tissue staining, determination of boric acid, cyanide and hydrochloric acid. |
production method | after diazotization of biganine, coupling with sodium 1, 4-aminonaphthalene sulfonate, followed by salting out, obtained by filtration and drying. The specific operation is: 48.4g of benzidine is dissolved in 10% ml of hydrochloric acid (containing 20ml of concentrated hydrochloric acid), ice-cooled to below 5 ° C., after adding 30ml of concentrated hydrochloric acid, aqueous solution prepared by 14.4g of sodium nitrite is added. After diazotization, the diazonium salt solution is slowly added to 150g of sodium para-aminonaphthalene sulfonate and a small amount of water. After half an hour of storage, 35g of sodium carbonate is slowly added with sufficient stirring to make the solution alkaline, after heating to about 80 °c, the reaction mixture was cooled, filtered, washed with saturated brine and dried to obtain a final product. Industrial preparation raw material consumption (kg/t) benzidine (100%) 200 sodium aminonaphthalene sulfonate (100%) 520 sodium nitrite (industrial) 160 hydrochloric acid (31%) 330 soda ash (industrial) 340 refined salt 2500 still Oil 9 ethanol 60 sodium acetate 35 yuan powder 50 |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |