Name | 4,5-dihydroxynaphthalene-2,7-disulphonic acid |
Synonyms | Chrmotropicacid Chromotropic acid 8-Dihydroxynaphthylene-3 4,5-dihydroxy-7-naphthalenedisulfonicacid 7-Naphthalenedisulfonicacid,4,5-dihydroxy-2 4,5-dihydroxynaphthalene-2,7-disulfonic acid 1,8-Dihydroxynaphthylene-3,6-Disulfonic Acid 4,5-DIHYDROXY-2,7-NAPHTHALENEDISULFONIC ACID 4,5-dihydroxy-2,7-naphthalenedisulfonic acid 1,8-DIHYDROXYNAPHTHALENE-3,6-DISULFONIC ACID 4,5-Dihydroxy-2,7-naphthalene disulfonic acid 4,5-dihydroxynaphthalene-2,7-disulphonic acid 4,5-Dihydroxy-2,7-naphthalene disulfonic acid1,8-Dihydroxynaph-thalene-3,6-disulfonic acid |
CAS | 148-25-4 |
EINECS | 205-712-7 |
InChI | InChI=1/C10H8O8S2/c11-8-3-6(19(13,14)15)1-5-2-7(20(16,17)18)4-9(12)10(5)8/h1-4,11-12H,(H,13,14,15)(H,16,17,18) |
Molecular Formula | C10H8O8S2 |
Molar Mass | 320.3 |
Density | 1.7929 (rough estimate) |
Boling Point | 429.2°C (rough estimate) |
Appearance | Crystallization |
pKa | -0.51±0.40(Predicted) |
Storage Condition | Inert atmosphere,Room Temperature |
Sensitive | Sensitive to light |
Refractive Index | 1.6000 (estimate) |
Physical and Chemical Properties | Solid crystals. Soluble in water. |
Use | Used in the manufacture of azo dyes and Anthraquinone dyes, and used as reagents |
HS Code | 29089990 |
Downstream Products | Chromotrope 2R |
Reference Show more | 1. Wu Pingxiang, Li Zhonghai. Optimization of purification process of camphor leaf lignan macroporous adsorption resin [J]. Food and Machinery, 2018, 034(003):186-191. |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
Chromoacid reaction and application | Chromoacid reaction is a reaction to check methylene dioxy. That is, the methylene dioxy group in the compound molecule is hydrolyzed by acid to produce formaldehyde, and then it is condensed with color-changing acid to form a purple to pink product. Gallic acid can also be used instead of chromotryptic acid to check methylene dioxy. [identification method of fake and inferior corn gluten meal] 1. check the color change of corn gluten meal in chromochromic acid. Protein essence (urea-formaldehyde polymer) decomposes under the action of sulfuric acid to generate formaldehyde, which forms a purple substance with chromochromic acid. Starch, protein, sugar and ammonium do not interfere with this reaction. 2. take 0.1~0.2g of sample into a dried 50mL beaker, add about 1mL of chromochromic acid (1g/L concentrated sulfuric acid solution), carefully heat it on the electric furnace until it has just produced light smoke, remove the beaker, add 10mL of water, if the solution turns purple, the sample contains protein essence, which is a fake product. 3. Microscopic examination. Place the sample under a body microscope and enlarge it by 10-20 times. If yellow fragile particles are found, carefully clip several particles into a 50mL beaker, drop about 0.5mL of chromochromic acid, slightly heat the electric furnace until it has just produced light smoke, slowly add 10-15mL of water after taking it off. If the solution turns purple, the sample contains protein essence, which is a fake product. |
use | this product is an intermediate of dye acid medium dark blue. This dye can be used for dyeing wool fabrics and is obtained by coupling 4-chloro-o-aminophenol with chromochromic acid after diazotization. used to manufacture azo dyes and anthraquinone dyes, and used as reagents determination of chromium, titanium and formaldehyde, determination of chromium, mercury, silver, titanium, chlorate, formaldehyde, nitrate and nitrite, azo dye intermediates. |
Production method | T acid (1-aminonaphthalene-3,6, 8-trisulfonate ammonium salt) is converted into sodium salt, and then made by alkali melting. When used as a dye intermediate in industry, its sodium salt is generally used, the appearance is light gray or gray paste, and the chromogenic acid content is not less than 50%. Pure sodium salt contains 2 molecules of crystal water, CAS number is [5808-22-0], is white needle-shaped or leaf-shaped crystal, easily soluble in water, melting point> 300 ℃. Chromotryptic acid can also be made from 4-chloro-5-hydroxy-2, 7-naphthalenediculfonic acid as raw material. |