2-Amino-4,8-naphthalenedisulfonic acid

CAS NO.：131-27-1
Empirical Formula: C10H9NO6S2
Molecular Weight: 303.31
MDL number: MFCD00035722
EINECS: 205-020-5
SAFETY DATA SHEET (SDS)
Update Date: 2026-05-28 03:57:55

What is 2-Amino-4,8-naphthalenedisulfonic acid?

Chemical properties

2-Aminonaphthalene-4,8-disulfonic acid [131-27-1]. (3-aminonaphthalene-1,5-disulfonic acid), Cassella acid, C acid, C10H9NO6S2, Mr 303.32, and its salts are readily soluble in water. Reduction with sodium amalgam desulfonates 2-Aminonaphthalene-4,8-disulfonic acid to give 2-aminonaphthalene-8-sulfonic acid, whereas boiling with dilute sulfuric acid results in desulfonation and hydrolysis to give 2- hydroxynaphthalene-4-sulfonic acid. Alkali fusion (KOH, 215℃) produces 2-amino-4-hydroxynaphthalene-8-sulfonic acid.

The Uses of 2-Amino-4,8-naphthalenedisulfonic acid

2-Amino-4,8-naphthalenedisulfonic Acid is used in green preparation method of direct blended blue D 3GL.

The Uses of 2-Amino-4,8-naphthalenedisulfonic acid

Cassella acid is an important diazo component for yellow direct and reactive dyes.

Production Methods

The iron(II) salt of 3-nitronaphthalene-1,5-disulfonic acid (nitro-Armstrong acid) is reduced with iron in dilute acid. A claimed improvement involves isolation of nitro-Armstrong acid from the nitration products of naphthalene-1,5-disulfonic acid as the crystalline magnesium salt prior to catalytic reduction to C acid.

Properties of 2-Amino-4,8-naphthalenedisulfonic acid

Boiling point:	205.8°C (rough estimate)
Density	1.6329 (rough estimate)
refractive index	1.7330 (estimate)
storage temp.	2-8°C
pka	-1.16±0.40(Predicted)
CAS DataBase Reference	131-27-1(CAS DataBase Reference)
EPA Substance Registry System	1,5-Naphthalenedisulfonic acid, 3-amino- (131-27-1)

Safety information for 2-Amino-4,8-naphthalenedisulfonic acid

Signal word	Warning
Pictogram(s)	Exclamation Mark Irritant GHS07
GHS Hazard Statements	H302:Acute toxicity,oral H315:Skin corrosion/irritation H319:Serious eye damage/eye irritation H335:Specific target organ toxicity, single exposure;Respiratory tract irritation
Precautionary Statement Codes	P261:Avoid breathing dust/fume/gas/mist/vapours/spray. P264:Wash hands thoroughly after handling. P264:Wash skin thouroughly after handling. P270:Do not eat, drink or smoke when using this product. P271:Use only outdoors or in a well-ventilated area. P280:Wear protective gloves/protective clothing/eye protection/face protection. P330:Rinse mouth. P362:Take off contaminated clothing and wash before reuse. P301+P312:IF SWALLOWED: call a POISON CENTER or doctor/physician IF you feel unwell. P302+P352:IF ON SKIN: wash with plenty of soap and water. P304+P340:IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing. P332+P313:IF SKIN irritation occurs: Get medical advice/attention. P337+P313:IF eye irritation persists: Get medical advice/attention. P405:Store locked up. P403+P233:Store in a well-ventilated place. Keep container tightly closed. P501:Dispose of contents/container to..…