1,8-Dihydroxynaphthylene-3,6-disulfonic acid
- CAS NO.:148-25-4
- Empirical Formula: C10H8O8S2
- Molecular Weight: 320.3
- MDL number: MFCD00003968
- EINECS: 205-712-7
- SAFETY DATA SHEET (SDS)
- Update Date: 2024-12-18 14:08:57

What is 1,8-Dihydroxynaphthylene-3,6-disulfonic acid?
Chemical properties
4,5-Dihydroxynaphthalene-2,7-disulfonic acid [148-25-4]. (1,8-dihydroxynaphthalene-3,6-disulfonic acid), chromotropic acid, C10H8O8S2, Mr 320.3: the disodium salt is readily soluble in water. Alkali fusion yields 1,3,8-trihydroxynaphthalene-6-sulfonic acid. Diazo coupling occurs in the 3- and 6-positions.
The Uses of 1,8-Dihydroxynaphthylene-3,6-disulfonic acid
Chromotropic acid is used as an analytical reagent and as a coupling component for a wide range of azo dyes, e.g., C.I. Acid Violet 6, C. I. Mordant Blue 13, and C.I. Direct Blue 84.
Definition
ChEBI: A naphthalenesulfonic acid that is naphthalene-2,7-disulfonic acid substituted by hydroxy groups at positions 4 and 5.
Production Methods
2-Hydroxynaphthalene-3,6,8- trisulfonic acid total liquor is concentrated and heated with caustic soda liquor to 158℃ for 20 – 30 h . The melt is diluted with water and poured into excess hydrochloric acid. Salt is added, sulfur dioxide expelled, and the mixture cooled to precipitate the product as the disodium salt in 88 % yield.
An alternative process is based on direct fusion (caustic liquor at 228℃ under pressure) of 1-aminonaphthalene-3,6,8-trisulfonic acid to chromotropic acid without isolating the intermediate oxy Koch acid.
Properties of 1,8-Dihydroxynaphthylene-3,6-disulfonic acid
Boiling point: | 429.2°C (rough estimate) |
Density | 1.7929 (rough estimate) |
refractive index | 1.6000 (estimate) |
storage temp. | Inert atmosphere,Room Temperature |
pka | -0.51±0.40(Predicted) |
CAS DataBase Reference | 148-25-4(CAS DataBase Reference) |
EPA Substance Registry System | 2,7-Naphthalenedisulfonic acid, 4,5-dihydroxy- (148-25-4) |
Safety information for 1,8-Dihydroxynaphthylene-3,6-disulfonic acid
Computed Descriptors for 1,8-Dihydroxynaphthylene-3,6-disulfonic acid
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