Chemical Properties
solid
Uses
A phenyl urea herbicide. Pre-emergent herbicide.
Definition
ChEBI: A member of the class of ureas that is urea in which both of the hydrogens attached to one nitrogen are substituted by methyl groups, and one of the hydrogens attached to the other nitrogen is substituted by a 3,4-dichlorophenyl group.
Uses
Pre-emergent herbicide.
General Description
Diuron is a white crystalline solid. Diuron is a wettable powder. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. Diuron can cause illness by inhalation, skin absorption and/or ingestion. Diuron is used as a herbicide.
Air & Water Reactions
Very slightly soluble in water.
Reactivity Profile
Diuron is incompatible with the following: Strong acids .
Health Hazard
INHALATION: May cause irritation of nose and throat. EYES: Irritation. SKIN: Moderately irritating to skin.
Description
Diuron (330-54-1) is used as an herbicide for weed control on
noncrop lands and agricultural crops such as asparagus, pineapple,
cotton, and sugarcane. It is also used as a sterilant in soil,
a mildewcide in paints and stains, and an algicide in fish
production.
Production Methods
The commercial production of diuron involves a multi-step chemical synthesis. It begins with the reaction of 3,4-dichloroaniline with phosgene or a safer substitute like triphosgene to form 3,4-dichlorophenyl isocyanate. This intermediate is then reacted with dimethylamine to produce diuron. The process requires careful control of temperature and pH to minimise side reactions and maximise yield. Final steps include purification, drying, and formulation.
Agricultural Uses
Herbicide: Diuron is a substituted urea herbicide used to control
a wide variety of annual and perennial broadleaf and
grassy weeds, as well as mosses. It is used on non-crop areas
and many agricultural crops such as fruit, cotton, sugar
cane, alfalfa, and wheat. Diuron works by inhibiting photosynthesis.
It may be found in formulations as wettable
powders and suspension concentrates.
Trade name
330541®; AF 101®; AI3-61438®;
AMETRON SC®; BOUNDRY®[C]; CHEMIURON®[C];
CEKIURON®; CRISURON®; DAILON®; DIATER®;
DI-ON®; DIREX®; DITOX®; DIUMATE® Diuron;
DIUREX®,[C]; DIUROL® Diuron; DIURON 4L®;
DMU®; DREXEL DIURON 4L®; DROPP ULTRA®;
DURAN®; DYNEX®[C] FARMCO DIURON®;
FORTEX SC®; FREEFLO®; GINSTAR®; HERBURON
500 BR®; HW 920®; KARMEX®[C]; K-4®; KARMEX
DIURON HERBICIDE®; KARMEX DW®; KROVAR
IDF®[C]; MARMER®; STRIKER®; SUP'R FLO®;
TELVAR®; TIGREX®; TREVISSIMO®; UNIDRON®;
UROX D®[C]; VONDURON®
Mechanism of action
Systemic, absorbed via roots, acts by strongly inhibiting photosynthesis
Potential Exposure
High-performance liquid chromatography may be used after extraction with methylene chloride. Measurement is made using an ultraviolet detector.Fish Tox 5 40.39243000 pbb (INTERMEDIATE).Moderately toxic to fish; highly toxic to aquaticinvertebrates
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.Note to physician: Treat for methemoglobinemia.Spectrophotometry may be required for precise determination of levels of methemoglobinemia in urine.
Environmental Fate
Biological. Degradation of radiolabeled diuron (20 ppm) was not observed after 2 weeks of culturing with Fusarium and two unidentified microorganisms. After 80 days, only 3.5% of the applied amount evolved as 14CO2 (Lopez and Kirkwood, 1974). In 8 weeks, <20% of diuron in soil (60 ppm) was detoxified (Corbin and Upchurch, 1967). 3,4-Dichloroaniline was reported as a minor degradation product of diuron in water (Drinking Water Health Advisory, 1989) and soils (Duke et al., 1991).
Under aerobic conditions, mixed cultures isolated from pond water and sediment degraded diuron (10 μg/mL) to CPDU, 3,4-dichloroaniline, 3-(3,4-dichlorophenyl)-1methylurea, carbon dioxide and a monodemethylated product. The extent of biodegradation varied with time, glycerol concentration and microbial population. The degradation halflife was <70 days at 30°C (Ellis and Camper, 1982).
Thom and Agg (1975) reported that diuron is amenable to biological treatment with acclimation.
Soil. Several degradation pathways were reported. The major products and reaction pathways include formation of 1-methyl-3-(3,4-dichlorophenol) ur
Incubation of diuron in soils releases carbon dioxide (Madhun and Freed, 1987). The rate of carbon dioxide formation nearly tripled when the soil temperature was increased from 25 to 35°C. Reported half-lives in an Adkins loamy sand are 705, 414 and 225 d
The half-lives for diuron in field soils ranged from 133 to 212 days with an average half-life of 328 days (Hill et al., 1955). Hill et al. (1955) studied the degradation of diuron using a Cecil loamy sand (1 ppm) and Brookstone silty clay loam (5 ppm) in the laboratory maintained at 27°C and 60% relative humidity. In both soils, diuron was applied on four separate occasions over 22 weeks. In both instances, the investigators observed 40% of the applied amount degraded in both soils.
In a field application study, diuron did not leach below 5 cm in depth despite repeated applications or water addition (Majka and Lavy, 1977).
Groundwater. According to the U.S. EPA (1986) diuron has a high potential to leach to groundwater.
Shipping
Phenyl urea pesticides, solid, toxic, n.o.s. requirea “POISONOUS/TOXIC MATERIALS” label. They fall inHazard Class 6.1 and Packing Group III.
Purification Methods
Recrystallise it from 95% EtOH [Beck et al. J Am Chem Soc 108 4018 1986]. [Beilstein 12 IV 1263.]
Toxicity evaluation
Diuron is a selective inhibitor of the Hill reaction in plant
photosynthesis. In some mammalian carcinogenic studies,
repeated high-dose exposure to diuron appeared to work as
a tumor promoter, and diuron may elicit tumor formation
by inducing cytotoxicity with subsequent sustained cell
proliferation.
Toxics Screening Level
The initial threshold screening level (ITSL) for Diuron is 7 μg/m3 (24-hour averaging time).
