1,2-Bis(4-chlorophenyl)diazene

251.11

251.11

0TL0OEH9RX

59160

2927000090

24.7

5.3

1.27±0.1 g/cm3(Predicted)

179 °C

375.2±27.0 °C(Predicted)

180.7ºC

1.608

1.71E-05mmHg at 25°C

P264, P270, P273, P280, P301+P312, P305+P351+P338, P330, P337+P313, P501

H302

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

|Warning|H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]|P264, P270, P273, P280, P301+P312, P305+P351+P338, P330, P337+P313, and P501|Aggregated GHS information provided by 38 companies from 1 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Formation of asymmetric and symmetric azobenzenes (eg 4,4'-dichloroazobenzene) from substituted aniline pairs in soil or peroxidase reaction mixture was studied.

4,4'-Dichloroazobenzene's production and use in the dye industry(1) may result in its release to the environment through various waste streams(SRC). Formation of asymmetric and symmetric azobenzenes (e.g. 4,4'-dichloroazobenzene) from substituted aniline pairs in soil or peroxidase reaction mixture may also occur(2).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 5100(SRC), determined from a structure estimation method(2), indicates that 4,4'-dichloroazobenzene is expected to be immobile in soil(SRC). Volatilization of 4,4'- dichloroazobenzene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 8.1X10-6 atm-cu m/mole(SRC), using a fragment constant estimation method(3). 4,4'-Dichloroazobenzene is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 6.6X10-5 mm Hg(4). Biodegradation of 4,4'-dichloroazobenzene may be important in anaerobic sediment-water environments(5).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 5100(SRC), determined from an estimation method(2), indicates that 4,4'-dichloroazobenzene is expected to adsorb to suspended solids and sediment in water(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 8.1X10-6 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 5.4 days and 44 days, respectively(SRC). However, this model underestimates the volatilization half-life of 4,4'-dichloroazobenzene since it does not take into account the effects of adsorption. This is apparent from the results of two EXAMS model runs, one in which the effect of adsorption was considered (half life = 13 months in a model pond) and one in which adsorption was ignored (half life = 21 days in a model pond)(5). According to a classification scheme(5), an estimated BCF of 10(SRC), from an estimated log Kow of 5.4(6) suggests the potential for bioconcentration in aquatic organisms is low. Biodegradation of 4,4'-dichloroazobenzene may be important in anaerobic sediment-water environments(7).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 4,4'-dichloroazobenzene, which has an estimated vapor pressure of 6.6X10-5 mm Hg at 25 °C(2), is expected to exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 4,4'-dichloroazobenzene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 15 days(SRC), calculated from its rate constant of 1.1X10-12 cu cm/molecule-sec at 25 °C(SRC), determined using a structure estimation method(3). Particulate-phase 4,4'-dichloroazobenzene may be removed from the air by wet and dry deposition(SRC).

The rate constant for the vapor-phase reaction of 4,4'-dichloroazobenzene with photochemically-produced hydroxyl radicals has been estimated as 1.1X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 15 days(SRC) at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 4,4'-Dichloroazobenzene is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2).

An estimated BCF of 10 was calculated for 4,4'-dichloroazobenzene(SRC), using an estimated log Kow of 5.4(1,SRC) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low.

Using a structure estimation method based on molecular connectivity indices(1), the Koc for 4,4'-dichloroazobenzene can be estimated to be 5100(SRC). According to a classification scheme(2), this estimated Koc value suggests that 4,4'-dichloroazobenzene is expected to be immobile in soil.

The Henry's Law constant for 4,4'-dichloroazobenzene is estimated as 8.1X10-6 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 4,4'-dichloroazobenzene is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 3.5 days(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 44 days(SRC). However, this model underestimates the volatilization half-life of 4,4'-dichloroazobenzene since it does not take into account the effects of adsorption. This is apparent from the results of two EXAMS model runs, one in which the effect of adsorption was considered (half life = 13 months in a model pond) and one in which adsorption was ignored (half life = 21 days in a model pond)(5). 4,4'-Dichloroazobenzene's Henry's Law constant(1) indicates that volatilization from moist soil surfaces may occur(SRC). 4,4'-Dichloroazobenzene is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated) vapor pressure of 6.6X10-5 mm Hg(SRC), determined from a fragment constant method(3).

Occupational exposure to 4,4'-dichloroazobenzene may occur through inhalation and dermal contact with this compound at workplaces where 4,4'-dichloroazobenzene is produced or used. (SRC)

THE MICROBIAL OXIDATION OF 4-CHLOROANILINE BY THE SOIL FUNGUS FUSARIUM OXYSPORUM WAS STUDIED...METABOLITES INCLUDED 4,4'-DICHLOROAZOXYBENZENE & 4,4'-DICHLOROAZOBENZENE.|Lignin peroxidase H2 (LP H2) from Phanerochaete chrysosporium oxidized 4 chloroaniline to form several oligomers. Included among the compounds identified were: 4,4' dichloroazobenzene, 2 (4 chloroanilino) 5 hydroxybenzoquinone di 4 chloroanil and 2 amino S (4 chloroanilino) benzoquinone di 4 chloroanil. In contrast to results by others, we showed that oligomers of 4 chloroaniline were also formed by the fungus in vivo. It was also demonstrated that, although these potentially toxic intermediates are made, they are also degraded.|4 chloroaniline was oxidized by soya cell wall peroxidases in the presence of hydrogen peroxide. The main product, an orange compound with a maximal absorbance at 455 nm, was probably 4,4' dichloroazobenzene. The optimum pH of the reaction was 4. Michaelis constants, determined as described by Dalziel, were 21 mM for 4 chloroaniline and 94 uM for hydrogen peroxide. Syringaldazine was an uncompetitive inhibitor of 4 chloroaniline peroxidation (Ki = 46 uM) and modified the progress of the reaction with the appearance of a lag period. By contrast, 4 chloroaniline was a non competitive inhibitor of syringaldazine peroxidation with a Ki value of 21 mmx at pH 7.5. Therefore, these two inhibiting effects were compatible with the presence of two binding sites for two different hydrogen donors. Both sites were linked by allosteric interactions. The inferences on chloroaniline binding are discussed.

Analysis of 4,4'-dichloroazobenzene in soil or peroxidase mixt by gas and thin-layer chromatography after formation from substituted aniline pairs.