Empirical Formula: C₆H₄N₂O₇S
Molecular Weight: 248.1702
EINECS: 201-876-9 
Melting point: 95-98 °C(lit.)
Index of Refraction: 1.643
Density: 1.826 g/cm³
Structure of 2,4-Dinitrobenzenesulfonic acid (CAS NO.89-02-1):
                           
IUPAC Name: 2,4-Dinitrobenzenesulfonic acid
Product Categories: Intermediates of Dyes and Pigments;Organic Building Blocks;Sulfonic/Sulfinic Acids

 2,4-Dinitrobenzenesulfonic acid (CAS NO.89-02-1) has been used for dye intermediate.

 2,4-Dinitrobenzenesulfonic acid (CAS NO.89-02-1) can be derived by sulfonation from 2,4 - Dinitrochlorobenzene . Take 1100L water into the sulfonation pot, and has it heated to 50 °C, then keep stirring fast when join 119kg light Magnesium oxide . Stirring a moment then add 750kg melt: 2,4 - Dinitrochlorobenzene , and heated to 65 °C, add 462kg weight Sodium sulfite solution (dubbed 4.5-5N concentration) in 4h. At last, when the reaction is completed, has them beng cooled to 55 °C. Adding Hydrochloric acid , then add 35kg salt, cooled to 20 °C, put it aside, filtering, then we will get the product.

Reported in EPA TSCA Inventory.

Poison by intravenous route. A skin and eye irritant. When heated to decomposition it emits very toxic fumes of NO_x and SO_x.
Hazard Codes: C
Risk Statements: 34 
R34:Causes burns.
Safety Statements: 26-36/37/39-45 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S36/37/39:Wear suitable protective clothing, gloves and eye/face protection. 
S45:In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)

 2,4-Dinitrobenzenesulfonic acid ,its cas register number is 89-02-1. It also can be called 2,4-Dinitrophenylsulfonic acid ;and Kyselina 2,4-dinitrobenzensulfonova .