IUPAC Name: 3,3'-Dichlorobenzidine
The MF of 3,3'-Dichlorobenzidine (91-94-1) is C₁₂H₁₀Cl₂N₂.

                   
The MW of 3,3'-Dichlorobenzidine (91-94-1) is 253.13.
Synonyms of 3,3'-Dichlorobenzidine (91-94-1): 3,3'-Dichlorobenzidine ; [1,1'-Biphenyl]-4,4'-diamine, 3,3'-dichloro- ; 3,3'-Dichlorbiphenyl-4,4'-diamin ; 3,3-Dichloro-(1,1'-biphenyl)-4,4'-diamine ; 3,3'-Dichloro-4,4'-diamino(1,1-biphenyl) ; 3,3'-Dichlorobenzidina
Product Categories: Intermediates of Dyes and Pigments;Aryl Amines MAK III, Category 2Volatiles/ Semivolatiles;2002/61/EC;Alpha Sort;D;DAlphabetic;DIA - DICMethod Specific;European Community: ISO and DIN;Method Specific;Oeko-Tex Standard 100;OLM04 Statement of WorkMethod Specific;CLP Standards;DIA - DICEPA
Form: colourless to white crystalline solid
Index of Refraction: 1.678  
EINECS: 202-109-0
Density: 1.381 g/ml
Flash Point: 186.6 °C 
Boiling Point: 385 °C
Storage Temp: 2-8°C
Stability: Stable

   3,3'-Dichlorobenzidine (91-94-1) is used in the dye industry, curing agent for isocyanate terminated resins.

A halogenated amine. Amines are chemical bases. They neutralize acids to form salts plus water. These acid-base reactions are exothermic. The amount of heat that is evolved per mole of amine in a neutralization is largely independent of the strength of the amine as a base. Amines may be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated by amines in combination with strong reducing agents, such as hydrides.

NTP 10th Report on Carcinogens. IARC Cancer Review: Group 2B IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 (1987),p. 193.(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 Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 29 (1982),p. 239.(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 Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 29 (1982),p. 239.(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) ; IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 4 (1974),p. 49.(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. Community Right-To-Know List. EPA Genetic Toxicology Program.

Confirmed carcinogen with experimental carcinogenic and tumorigenic data. Human mutation data reported. When heated to decomposition it emits very toxic fumes of Cl⁻ and NO_x.
Safety information of 3,3'-Dichlorobenzidine (91-94-1):
Hazard Codes  T,N,F
Risk Statements 
45  May cause cancer
21  Harmful in contact with skin
43  May cause sensitization by skin contact
50/53  Very Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment
39/23/24/25  Toxic: danger of very serious irreversible effects through inhalation, in contact with skin and if swallowed
11  Highly Flammable
Safety Statements 
53  Avoid exposure - obtain special instruction before use
45  In case of accident or if you feel unwell, seek medical advice immediately (show label where possible)
60  This material and/or its container must be disposed of as hazardous waste
61  Avoid release to the environment. Refer to special instructions safety data sheet
36/37  Wear suitable protective clothing and gloves
16  Keep away from sources of ignition - No smoking
7  Keep container tightly closed
RIDADR  UN 3077 9/PG 3
WGK Germany  3
RTECS  DD0550000

OSHA PEL: Cancer Suspect Agent
ACGIH TLV: Animal Carcinogen
DFG MAK: DFG TRK: Animal Carcinogen, Suspected Human Carcinogen
NIOSH REL: (Benzidine-based Dye) Reduce to lowest feasible level

For occupational chemical analysis use OSHA: #ID-65 or NIOSH: Benzidine and 3,3′-Dichlorobenzidine, 5509.