Environmental Engineering Reference
In-Depth Information
Malathion , Parathion , and dimethoate , on photodecomposition in air, undergo isomeriza-
tion as:
S
O
OC 2 H 5
SC 2 H 5
NO 2
P
P
O
NO 2
O
OC 2 H 5
OC 2 H 5
Parathion
Isoparathion
O
O
S
O
CH 3 S
CH 3 O
CH 2
S
C
NH CH 3
P
S
CH 2
C
NH CH 3
P
CH 3 O
CH 3 O
which, on further decomposition, are converted into phosphoric acid and p-nitrophenol.
Parathion undergoes photoreduction of the nitro group via nitroso and hydroxyamino
groups and forms azoxy dimer as
Quinalphos is widely used as an insecticide. Photodegradation is one of the main modes
of degradation in the environment. Quinalphos, in alcoholic solution, undergoes photo-
chemical degradation as
NH 2
R
NHOH
R
NO 2
R
NO
R
Parathion
O
R
R
N
N
R
R
N
N
Azo
Azoxy
OH
S
OC 2 H 5
OC 2 H 5
R
O
P
R
N
N
R
2-Hydroxyazo
S
S
OC 2 H 5
N
OC 2 H 5
O
N
P
Alcohol
O
P
OC 2 H 5
OC 2 H 5
OC 2 H 5
N
N
C 2 H 5 OH
uv
O
S
OC 2 H 5
N
O
OC 2 H 5
P
N
O
P
OC 2 H 5
OC 2 H 5
N
N
CH (OH) CH 3
Photodegradation is faster in soil (t ½ 2-5 days)
 
Search WWH ::




Custom Search