General Description
Colorless crystals. Non corrosive. Insoluble in water. Used as an herbicide.
Air & Water Reactions
Insoluble in water. Reacts slowly with water. The reaction is promoted by acid such that the pH is less than 5.0 (1/2 life of 24-48 hrs.). Reaction is also promoted by polar organic solvents such as methanol and acetone.
Potential Exposure
A selective systemic sulfonylurea herbicide used to control most broadleaf weeds and some annual grasses in wheat, barley, oats, duram, rye, triticale, and flax. Applied to noncrop sites such as rights-of-way, fence rows, and roadsides.
First aid
If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions) if breathing has stopped, and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit
Shipping
UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required.
Incompatibilities
Slowly hydrolyzes in water, releasing ammonia and forming acetate salts. May bencompatible 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, epoxides.
Description
Chlorsulfuron is one of the first sulfonylurea herbicides
developed and commercialized by DuPont. Dr George Levitt
and his team at DuPont first synthesized chlorsulfuron in 1976,
and it was commercialized for use as a herbicide in 1981. It is
currently registered by DuPont in the United States, Canada,
the European Union, Russia, the Ukraine, Australia, New
Zealand, South Africa, Saudi Arabia, and in several countries of
South America.
Compared with many other herbicides that are applied at
levels of pounds per acre (or kilograms per acre), sulfonylureas
are highly effective at use rates of less than an ounce per acre
(approximately 6 g per acre for chlorsulfuron).
Waste Disposal
It is the responsibility of chemical waste generators to determine the toxicity and physical properties and of a discarded chemical and to properly identify its classification and certification as a hazardous waste and to determine the disposal method. United States Environmental Protection Agency guidelines for the classification determination are listed in 40 CFR Parts 261.3. In addition, waste generators must consult and follow all regional, national, state, and local hazardous waste laws to ensure complete and accurate classification and disposal methods. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material’s impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations
Definition
ChEBI: Chlorsulfuron is an N-sulfonylurea that is N-carbamoyl-2-chlorobenzenesulfonamide in which one of the hydrogens attached to the non-sulfonylated nitrogen has been replaced by a 4-methoxy-6-methyl-1,3,5-triazin-2-yl group. A herbicide used for the control of broadleaf weeds in wheat, barley and oats. It has a role as an agrochemical, a herbicide and an EC 2.2.1.6 (acetolactate synthase) inhibitor. It is a N-sulfonylurea, a member of monochlorobenzenes and a methoxy-1,3,5-triazine.
Production Methods
Chlorsulfuron is produced commercially through a multi-step synthesis that centres on the use of o-chlorobenzenesulfonamide as a key intermediate. The process begins with the preparation of this sulfonamide, which is then reacted with a triazine derivative, specifically, 4-methoxy-6-methyl-1,3,5-triazin-2-amine. This reaction forms a sulfonylurea linkage, resulting in the active compound, 2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoyl]benzenesulfonamide. The synthesis is carried out under controlled conditions to ensure high yield and purity, often using organic solvents and catalysts to facilitate the coupling reaction.
Agricultural Uses
Herbicide: A selective systemic herbicide used to control most
broadleaf weeds and some annual grasses in wheat, barley,
oats, duram, rye, triticale and flax. Applied to non-crop
sites such as rights-of-way, fence rows and roadsides.
Trade name
DPX 4189®; FINESSE®; GLEAN®;
GLEAN 20DF®; LANDMARK® MP; LASHER®;
RIVERDALE CORSAIR®; TELAR® DF
Mechanism of action
Selective, systemic, absorbed by roots and foliage, acts by inhibiting cell division. Inhibits plant amino acid synthesis - acetohydroxyacid synthase AHAS
Environmental Fate
Soil. Degrades in soil via hydrolysis followed by microbial degradation forming low
molecular weight, inactive compounds. The estimated half-life was reported to range from
4 to 6 weeks (Hartley and Kidd, 1987; Cremlyn, 1991). Microorganisms capable of
degrading chlorsulfuron are Aspergillis niger, Streptomyces griseolus and Penicillium sp.
(Humburg et al., 1989). One transformation product reported in field soils is 2-chlorobenzenesulfonamide (Smith, 1988)
The reported dissipation rate of chlorsulfuron in surface soil is 0.024/day (Walker and
Brown, 1983). The persistence of chlorsulfuron decreased when soil temperature and
moisture were increased (Walker and Brown, 1983; Thirunarayanan et al., 1985)
Plant. Chlorsulfuron is metabolized by plants to hydroxylated, nonphytotoxic compounds including 2-chloro-N-(((4-methoxy-6-methyl-1,3,5-triazin-2-yl)-amino)carbonyl)benzenesulfonamide (Duke et al., 1991). Devine and Born (1985) and Peterson and
Photolytic. The reported photolysis half-lives of chlorsulfuron in distilled water, methanol and natural creek water at λ >290 nm were 18, 92 and 18 hours, respectively. In all
cases, 2-chlorobenzene sulfonamide, 2-methoxy-4-methyl-6-amino-1,3,5-triazine and
trace amounts of the tentatively identified compound nitroso-2-chlorophenylsulfone
formed as photoproducts (Herrmann et al., 1985).
Metabolic pathway
Chlorsulfuron is metabolized in wheat and in tolerant
broadleaves via different pathways where
hydroxylation occurs on the methyl group of the
triazine ring and at the phenyl ring of the chlorsulfuron
in respective plants. With chemical degradation of
chlorsulfuron on dry minerals (Syst.), two pathways of
degradation are observed, one of which is direct
Toxicity evaluation
Chlorsulfuron has a moderate to short-lived fate in the environment.
It does not bioaccumulate and is not volatile. In the
environment, chlorsulfuron degrades via a combination of
biotic and abiotic processes. Chlorsulfuron degrades in acidic
solutions and soil by cleavage of the sulfonylurea bridge, Odemethylation,
and hydroxylation. Chlorsulfuron is metabolized
by soil microbes to numerous minor degradation products, is mineralized to CO2, and sequestered as nonextractable
residues. Photodegradation is not a significant
pathway of dissipation for chlorsulfuron in the environment.
Hydrolytic processes are not expected to be a major contributing
factor in the environmental degradation of chlorsulfuron,
and would only be significant at acidic pH.
