3,3'-Dichlorobenzidine

Description

3,30-Dichlorobenzidine is a gray or purplecrystalline solid. Molecular weight =253.14; Boilingpoint =368℃; Freezing/Melting point = 132.8℃;Autoignition temperature =350℃. Hazard Identification(based on NFPA-704 M Rating System): Health 0,Flammability 1, Reactivity 0. Practically insoluble in water;solubility = 0.07% at 15℃.

Chemical properties

colourless to white crystalline solid

Chemical properties

3,3’-Dichlorobenzidine is a gray or purple crystalline solid.

Physical properties

Colorless to grayish-purple needles or crystals with a mild or pungent odor

The Uses of 3,3'-Dichlorobenzidine

Intermediate in the manufacture of azo dyes and pigments for printing inks, textiles, paints, plastics, and crayons; curing agent for isocyanate-terminated polymers and resins; rubber compounding ingredient; analytical determination of gold; formerly used as chemical intermediate for direct red 61 dye.

The Uses of 3,3'-Dichlorobenzidine

Used in the production of yellow and red pigments for the printing ink, textile, paper, paint, rubber, plastic, and related industries

Definition

ChEBI: 3,3'-Dichlorobenzidine is an organochlorine compound, a member of biphenyls and a member of monochlorobenzenes.

General Description

Gray to purple crystalline powder. Insoluble in water. Very toxic. Used in the dye industry, curing agent for isocyanate terminated resins.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

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.

Health Hazard

3,3'-Dichlorobenzidine (DCB) is carcinogenic in several animal species.

Fire Hazard

Combustible.

Safety Profile

Confirmed carcinogen with experimental carcinogenic and tumorigenic data. Human mutation data reported. When heated to decomposition it emits very toxic fumes of Cl and NOx.

Potential Exposure

A halide-and amine-substituted aromatic compound used in the dye industry, curing agent for isocyanate terminated resins. The major uses of dichlorobenzidine are in the manufacture of pigments for printing ink, textiles, plastics, and crayons and as a curing agent for solid urethane plastics. There are no substitutes for many of its uses. Additional groups that may be at risk include workers in the printing or graphic arts professions handling the 3,3’-DCB-based azo pigments. 3,3’-DCB may be present as an impurity in the pigments, and there is some evidence that 3,3’-DCB may be metabolically liberated from the azo pigment

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.

Carcinogenicity

Studies in several test systems have shown DCB to be genotoxic in vitro and in vivo and suggest that this effect most likely mediates the carcinogenicity of the chemical. In vitro, DCB has induced sister chromatid exchanges, unscheduled DNA synthesis, and positive responses in bacterial Salmonella assays; in vivo DCB induced micronuclei in polychromatic erythrocytes in male mice and fetuses.
Because of demonstrated potent carcinogenicity in multiple animal species, evidence of genotoxicity, and structural relationship to the known bladder carcinogen benzidine, DCB should be regarded as a probable human carcinogen and exposure by any route should be avoided.
3,3￠-Dichlorobenzidene has no threshold limit value (TLV) exposure limit and is classified as an A3, confirmed animal carcinogen with unknown relevance to humans, and a notation for skin absorption.

Source

Synthesized from o-chloronitrobenzene in the presence of NaOH and zinc dust (Shriner et al., 1978).

Environmental Fate

Biological. In activated sludge, 2.7% mineralized to carbon dioxide after 5 d (Freitag et al., 1985). Sikka et al. (1978) reported 3,3′-dichlorobenzidine is resistant to degradation by indigenous aquatic microbial communities in a 4-wk period. Under aerobic and anaerobic conditions, 3,3′-dichlorobenzidine is mineralized very slowly (Boyd et al., 1984; Chung and Boyd, 1987). Nyman et al. (1997a) studied the transformation of 3,3′-dichlorobenzidine under laboratory controlled conditions at 20 °C. Wet sediment (50 g) and water (150 mL) from Lake Macatawa, Holland, MI were placed in glass serum bottles and purged with nitrogen to ensure anaerobic conditions to which 3,3′-dichlorobenzidine was added. The bottles were incubated in the dark at 20 °C for 12 months. Soil and water samples were retrieved periodically for transformation product identification using HPLC. The investigators identified 3-chlorobenzidine as a transient metabolite from the biological transformation of 3,3′-dichlorobenzidine. 3-Chlorobenzidine rapidly dechlorinated forming the end product benzidine.
Photolytic. An aqueous solution subjected to UV radiation caused a rapid degradation (half-life <10 min) to monochlorobenzidine, benzidine, and several unidentified, brightly-colored, waterinsoluble chromophores (Banerjee et al., 1978). In a similar experiment, 3,3′-dichlorobenzidine in an aqueous solution was subjected to radiation at λ=310 nm for approximately 15 min. During the period of irradiation, concentrations of 3,3′-dichlorobenzidine decreased rapidly. 3-Chlorobenzidine formed as a transient intermediate which underwent dechlorination forming a benzidine, a stable photoproduct. Depending upon the wavelength used, the benzidine yields ranged from 8 to 12% of the total 3-chlorobenzidine transformed (Nyman et al., 1997). A carbon dioxide yield of 41.2% was achieved when 3,3′-dichlorobenzidine adsorbed on silica gel was irradiated with light (λ >290 nm) for 17 h (Freitag et al., 1985).
Chemical/Physical. 3,3′-Dichlorobenzidine will not hydrolyze to any reasonable extent (Kollig, 1993).
At influent concentrations of 1.0, 0.1, 0.01, and 0.001 mg/L, the GAC adsorption capacities at were 300, 190, 120, and 73 mg/g, respectively (Dobbs and Cohen, 1980).

storage

Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with thischemical you should be trained on its proper handling andstorage. Store in tightly closed containers in a cool, wellventilated area. A regulated, marked area should be established where this chemical is handled, used, or stored incompliance with OSHA Standard 1910.1045

Shipping

UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required

Purification Methods

Crystallise the benzidine from EtOH, pet ether (m 133o) or *benzene. [Beilstein 13 H 234, 13 I 67, 13 II 106, 13 III 477, 13 IV 384.] CARCINOGEN.

Incompatibilities

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, and epoxides. Achemical base: neutralize acids to form salts plus water with an exothermic reaction. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generatedby amines in combination with strong reducing agents such as hydrides, nitrides, alkali metals, and sulfides.

Waste Disposal

Incineration (816C, 0.5 second for primary combustion; 1204C, 1.0 second for secondary combustion). The formation of elemental chlorine can be prevented through injection of steam ormethane into the combustion process. nitrogen oxides may be abated through the use of thermal or catalytic devices. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal