CAS 7153-21-1 corresponds to sodium 2,7-dihydroxynaphthalene-3,6-disulfonate, which is a naphthalene sulfonate salt that is soluble in water and easily oxidizes and changes color when exposed to air. It is mainly used as a metal ion chelating indicator and dye/organic synthesis intermediate.

Core physical and chemical properties
-Chemical formula: C ₁₀ H ₆ Na ₂ O ₈ S ₂; Molecular weight: 364.26
-Appearance: beige to off white crystalline powder, gradually turning dark blue when exposed to air, with blue fluorescence in aqueous solution
-Melting point: 46-48 ° C; solubility: easily soluble in water
-EINECS number: 230-499-2; Alias: 3,6-dihydroxy-2,7-naphthalenedisulfonic acid disodium salt (note: not “color changing acid disodium”, the latter has a CAS of 5808-22-0 and a structure of 1,8-dihydroxy isomer)

main purpose
1. Analytical reagents: used as chelating indicators for colorimetric determination of metal ions such as chromium (Cr), titanium (Ti), mercury (Hg), etc
2. Synthesis intermediates: used for the preparation of azo dyes, anthraquinone dyes, and organic synthesis reactions
3. Other fields: Some materials mention the use of printing and dyeing auxiliaries and material synthesis

Safety and Storage
-Danger: Causes skin irritation (H315), severe eye irritation (H319)
-Protective measures: Wear protective gloves/goggles during operation, and immediately rinse with soapy water or clean water after contact
-Storage conditions: Store in a sealed, cool, dry place away from light to prevent oxidation and discoloration

Attention: This substance is often confused with “disodium chromophorate” (CAS 5808-22-0, 1,8-dihydroxy isomer), as they have different hydroxyl positions and significant differences in physicochemical properties and melting points (disodium chromophorate melting point>300 ° C). Do not mix them together.

Products :

Disodium 3,6-dihydroxynaphthalene-2,7-disulphonate CAS 7153-21-1
Write your message here and send it to us