2-Naphthylamine-5,7-disulfonic acid

CAS NO.：118-33-2
Empirical Formula: C10H9NO6S2
Molecular Weight: 303.31
MDL number: MFCD00021513
EINECS: 204-246-1
SAFETY DATA SHEET (SDS)
Update Date: 2025-07-16 09:55:40

What is 2-Naphthylamine-5,7-disulfonic acid?

Chemical properties

White glossy long prismatic needle-like crystals, the crystals precipitated from water contain 5 molecules of crystal water. The solubility in water at 20°C is 23%. Its monosodium salt and monopotassium salt are commonly used in industry, both of which are soluble in water, and the salt solution has green fluorescence.

The Uses of 2-Naphthylamine-5,7-disulfonic acid

2-Naphthylamine-5,7-disulfonic acid is an intermediate for the preparation of J acid, bis-J acid, phenyl J acid and scarlet acid.

Hazard

Skin - Rabbit 2 mg/24h severe; Eye - Rabbit 0.75 mg/24h severe

Flammability and Explosibility

Not classified

Synthesis

2-Naphthylamine-5,7-disulfonic acid can be obtained by hydrolysis of 2-naphthylamine-1,5,7-trisulfonic acid. Add sulfuric acid, sodium sulfate and 2-naphthylamine-1,5,7-trisulfonic acid into water, keep warm at 110-120°C for 4 hours, cool and filter, and wash in sodium sulfate solution to obtain the product.

Properties of 2-Naphthylamine-5,7-disulfonic acid

Boiling point:	568.34℃[at 101 325 Pa]
Density	1.769±0.06 g/cm3(Predicted)
vapor pressure	0Pa at 25℃
pka	-0.91±0.40(Predicted)
Water Solubility	229g/L at 15℃
CAS DataBase Reference	118-33-2(CAS DataBase Reference)
EPA Substance Registry System	1,3-Naphthalenedisulfonic acid, 6-amino- (118-33-2)

Safety information for 2-Naphthylamine-5,7-disulfonic 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. P280:Wear protective gloves/protective clothing/eye protection/face protection. 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. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.