3,3'-dichlorobenzidine

91-94-1

253.13

No 3,3'-dichlorobenzidine was lost from soil due to
volatilization during persistence studies over 32 and 52 weeks
under aerobic and anaerobic conditions, respectively (Boyd et
al. 1984).

The distribution coefficient of 3,3'-dichlorobenzidine to 
natural sediments at pH 7 ranged from 26.7 to 128. 
The 
adsorption was initially very rapid. 
Adsorption at pH 9 was 
reduced by 30-50% and desorption was low. 
Attempts to extract 
3,3'-dichlorobenzidine from the sediment revealed that it was 
very tightly bound (Appleton et al. 1978).

3,3'-Dichlorobenzidine is strongly adsorbed to Brookston clay 
loam and Rubicon sand, with the distribution constant being 
1100 and 273, respectively (Boyd et al. 1984).

Atmospheric photolysis half-life:
4.5min - 1.5min, based upon measured half-life for direct
photolysis in distilled water in midday summer sunlight,
scientific judgement based upon the direct photolysis half-life
and approximate winter sunlight intensity.

Photooxidation half-life in air:
9.05hr - 0.905hr, scientific judgement based upon estimated
rate constant for reaction with hydroxyl radicals in air
(Howard 1991).

3,3'Dichlorobenzidine has a strong absorption band at 282 nm
and degrades rapidly in dilute aqueous solutions (half-life 90
sec) when exposed to noonday summer sunlight. 
The
photodegradation products are 3-chlorobenzidine, benzidine and
water-insoluble colored materials (Banerjee et al. 1978).

Aquatic photolysis half-life:
4.5min - 1.5min, based upon measured half-life for direct
photolysis in distilled water in midday summer sunlight,
sientific judgement based upon the direct photolysis half-life
and approximate winter sunlight intensity.

Photooxidation half-life in water:
72.5d - 1.3d, scientific judgement based upon estimated rate
constant for reactions of representative aromatic amines with
OH and RO2. 
It is assumed that 3,3`-dichlorobenzidine reacts
twice as fast as aniline (Howard 1991).

Short-lived intermediates are also observed when chlorine-water
is added to a dilute aqueous solution of 3,3'dichlorobenzidine.

Half-lives of 3-4 minutes were determined in laboratory
irradiation experiments, which also revealed that the
photodegradation was acid catalyzed. 
The photolability of the
compound is much lower in organic solvents, which may lead to
an enhanced stability in water contaminated with hydrocarbons)
(Banerjee et al. 1978).

Unsubstituted benzidine is very rapidly oxidized by Fe(III) and
certain other naturally occurring cation, while no data could
be found for 3,3'-dichlorobenzidine. 
While the
chlorosubstituted benzidine would have less a tendency to
oxidize, this type of chemical reaction could be very important
invironmentally both in natural water and in soil (Callahan 
et al. 1979) ( Demirjian et al. 1987).

Aerobic half-life:
6mo - 4w, scientific judgement based upon data from a lake 
die-away study and a soil die-away test (Howard 1991).

Anaerobic half-life:
24mo - 16w, scientific judgement based upon estimated 
unacclimated aqueous aerobic biodegradation half-life
(Howard 1991).

Biodegradation:
1% by BOD
period: 28d
substance: 100 mg/l
sludge: 30 mg/l
(MITI 1992)

Confirmed to be non-accumulative or low accumulative (Anon.
1987).