Solvent Red 24

Structure of Scarlet red (CAS NO.85-83-6):

IUPAC Name: 1-[[2-methyl-4-(2-methylphenyl)diazenylphenyl]hydrazinylidene]naphthalen-2-one 
Empirical Formula: C₂₄H₂₀N₄O
Molecular Weight: 380.4418 
EINECS: 201-635-8 
Index of Refraction: 1.645
Molar Refractivity: 115.658 cm³
Molar Volume: 319.052 cm³
Polarizability: 45.85×10^-24cm³
Surface Tension: 46.131 dyne/cm
Density: 1.192 g/cm³
Flash Point: 424.365 °C
Enthalpy of Vaporization: 95.104 kJ/mol 
Melting Point: 199 °C (dec.)(lit.)
Boiling Point: 618.845 °C at 760 mmHg
Vapour Pressure: 0 mmHg at 25 °C 
Stability: Stable. Incompatible with strong oxidizing agents. 
Product Categories: Organics;Solvent Dyestuff
Physical Appearance: dark red to brown crystals or powder

In industry, Scarlet red (CAS NO.85-83-6) is used to color nonpolar substances like oils, waxes, fats,  various hydrocarbon products,greases, and acrylic emulsions. Sudan IV is also used in United Kingdom as a fuel dye to dye lower-taxed heating oil .  It is also known as Oil Tax Red. As a food dye, Sudan IV is considered an illegal dye.

IARC Cancer Review: Group 3 IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 ,1987,p. 56.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 8 ,1975,p. 217.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Human No Adequate Data IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 8 ,1975,p. 217.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . Reported in EPA TSCA Inventory.

Hazard Codes: Xi,T
Risk Statements: 36/38-45 
R36/38:Irritating to eyes and skin. 
R45:May cause cancer.
Safety Statements: 26-36-53-45 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S36:Wear suitable protective clothing. 
S53:Avoid exposure - obtain special instructions before use. 
S45:In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)
WGK Germany: 3
RTECS: QL5775000
Questionable carcinogen with experimental tumorigenic data. Mutation data reported. When heated to decomposition it emits toxic fumes of NO_x.

  Scarlet red , its cas register number is 85-83-6. It also can be called 1-(4-o-Tolylazo-o-tolylazo)-2-naphthol ; 2',3-Dimethyl-4-(2-hydroxynaphthylazo)azobenzene ; 2-Naphthol, 1-((4-(o-tolylazo)-o-tolyl)azo)- ; Biebrich Scarlet BPC ; Biebrich Scarlet R medicinal ; Biebrich Scarlet Red ; Brasilazina Oil Red B ; Cerven rozpoustedlova 24 ; Fast Oil Red B ; Fat Soluble Dark Red ; Hidaco Oil Red ; Lacquer Red VS  ; Oil Red ZD ; Oil Scarlet ; Oil Scarlet (VAN) ; Orient Oil Red RR ; Phenoplaste Organol Red B ; Rubrum scarlatinum ; Sarlach R ; Scarlet red, biebrich ; Scharlachrot ; alpha-Tolylazo-o-tolylazo-beta-naphthol ; o-Tolueneazo-o-toluene-beta-naphthol ; o-Tolueneazo-o-tolueneazo-beta-naphthol ; o-Tolylazo-o-tolylazo-2-naphthol ; o-Tolylazo-o-tolylazo-beta-naphthol .