SUDAN II

Synonym(s):1-(2,4-Xylylazo)-2-naphthol;Solvent Orange 7

CAS NO.：3118-97-6
Empirical Formula: C18H16N2O
Molecular Weight: 276.33
MDL number: MFCD00003896
EINECS: 221-490-4
SAFETY DATA SHEET (SDS)
Update Date: 2026-01-19 18:11:36

What is SUDAN II?

Chemical properties

Red to orange-brownish powder

The Uses of SUDAN II

Sudan II is a fat soluble red synthetic azo dye. Sudan II is reduced to potentially carcinogenic aromatic amines by human intestinal bacteria. Dyes and metabolites, Environmental Testing.

What are the applications of Application

Sudan II is a lipid soluble, diazo dye useful for staining triglycerides in animal tissues (frozen sections)

Preparation

mixed N,N-dimethylaniline diazotization, and Naphthalen-2-ol coupling.

Definition

ChEBI: Sudan II is a member of azobenzenes.

General Description

Red crystals. Insoluble in water.

Air & Water Reactions

Azo dyes can be explosive when suspended in air at specific concentrations. Insoluble in water.

Reactivity Profile

SUDAN II is an azo compound. Toxic gases are formed by mixing azo compounds with acids, aldehydes, amides, carbamates, cyanides, inorganic fluorides, halogenated organics, isocyanates, ketones, metals, nitrides, peroxides, phenols, epoxides, acyl halides, and strong oxidizing or reducing agents. Flammable gases are formed by mixing materials in this group with alkali metals. Explosive combination can occur with strong oxidizing agents, metal salts, peroxides, and sulfides.

Flammability and Explosibility

Not classified

Safety Profile

Questionable carcinogen with experimental carcinogenic data. Mutation data reported. When heated to decomposition it emits toxic fumes of NOx.

Properties and Applications

red orange. Melting point 166 ℃ (from the glacial acetic acid crystallization out). Soluble in ethanol, acetone and benzene as the red orange. In concentrated sulfuric acid for cherry red, dilution still for cherry red, and then into the orange and red brown with precipitation; In concentrated nitric acid for brilliant orange solution, and then gradually become dark; In 10% of sodium hydroxide solution insoluble, for yellow sanguine. Dye alcohol solution to join concentrated hydrochloric acid for orange solution; Add sodium hydroxide to become red.

Standard	Light Fastness	Heat-resistant(℃)		water	Sodium Carbonate(5%)	Hydrochloric acid(5%)
		Melting point	Stable
ISO	Good	166	100	Insoluble	Well	Well

Properties of SUDAN II

Melting point:	156-158 °C(lit.)
Boiling point:	419.24°C (rough estimate)
Density	1.1318 (rough estimate)
vapor pressure	0Pa at 25℃
refractive index	1.5800 (estimate)
storage temp.	Hygroscopic, Refrigerator, Under inert atmosphere
solubility	Chloroform (Slightly), DMSO (Slightly, Heated, Sonicated), Ethyl Acetate (Slight
form	Powder
Colour Index	12140
pka	13.52±0.50(Predicted)
color	Red to orange-brownish
Water Solubility	54.45μg/L at 25℃
Stability:	Hygroscopic
CAS DataBase Reference	3118-97-6
IARC	3 (Vol. 8, Sup 7) 1987
EPA Substance Registry System	C.I. Solvent Orange 7 (3118-97-6)

Safety information for SUDAN II

Signal word	Warning
Pictogram(s)	Exclamation Mark Irritant GHS07 Health Hazard GHS08
GHS Hazard Statements	H315:Skin corrosion/irritation H319:Serious eye damage/eye irritation H335:Specific target organ toxicity, single exposure;Respiratory tract irritation H351:Carcinogenicity
Precautionary Statement Codes	P201:Obtain special instructions before use. P261:Avoid breathing dust/fume/gas/mist/vapours/spray. P280:Wear protective gloves/protective clothing/eye protection/face protection. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing. P405:Store locked up.