General Description
Colorless crystals. Decomposed by either strong acid or base. Used as a selective herbicide.
Reactivity Profile
A bridged diphenyl.
Air & Water Reactions
Slightly soluble in water (3 mg/l).
Hazard
Moderately toxic by ingestion and skin contact. Low toxicity by inhalation.
Potential Exposure
Diclofop-methyl is a chlorophenoxy;
aryloxyphenoxypropionate acid selective postemergenceherbicide used to control wild oats and annual grassy weeds
in grain and vegetable crops: alfalfa, carrots, celery, box,
field and French beans, barley, wheat, brassicas, parsnips,
peas, potatoes, rapeseed (canola), soy beans, oilseed rape,
onions, sugar beets and lettuce. Some uses are classified
RUP
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. Do not induce vomiting
when formulations containing petroleum solvents are
ingested. Otherwise, give large quantities of water and
induce vomiting. Do not make an unconscious person vomit
Shipping
UN3345 Phenoxyacetic acid derivative pesticide,
solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous
materials. UN3348 Phenoxyacetic acid derivative pesticide,
liquid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous
material. UN3077 Environmentally hazardous substances,
solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous
hazardous material, Technical Name Required. Note:
Commercial product may also be a liquid in a flammable
carrier.
Incompatibilities
Incompatible with oxidizers, chlorates
nitrates, peroxides, sulfuric acid, caustics, ammonia,
aliphatic amines, alkanolamines, isocyanates, alkylene
oxides, and epichlorohydrin.
Description
Diclofop-methyl is a grass weed herbicide. It has a low aqueous solubility, a low risk of leaching to groundwater and is relatively volatile. It is non-persistent in soils but may be persistent in aquatic systems under certain conditions. It is moderately toxic to mammals if ingested and there is some concern that exposure may cause cancer or adverse reproduction / developmental effects. It is moderately toxic to birds, most aquatic organisms, earthworms and honeybees but is not toxic to honeybees.
Chemical Properties
A white crystalline solid. Odorless. Can also
be commercially available as a clear to dark brown liquid
with a typical solvent odor
Waste Disposal
In accordance with
40CFR165, follow recommendations for the disposal of
pesticides and pesticide containers. Containers must be disposed of properly by following package label directions or
by contacting your local or federal environmental control
agency, or by contacting your regional EPA office
Definition
ChEBI: Methyl 2-[4-(2,4-dichlorophenoxy)phenoxy]propanoate is a methyl ester resulting from the formal condensation of the carboxylic acid group of 2-[4-(2,4-dichlorophenoxy)phenoxy]propanoic acid with methanol. It is an aromatic ether, a dichlorobenzene, a diether and a methyl ester.
Production Methods
The commercial production of diclofop-methyl typically involves a multi-step organic synthesis starting from phenoxyacetic acid derivatives. The key intermediate is diclofop acid, which is synthesised by chlorinating and etherifying specific aromatic compounds to introduce the 2,4-dichlorophenoxy moiety. This acid is then esterified with methanol in the presence of an acid catalyst, commonly sulphuric acid or a similar agent, to form diclofop-methyl, the active herbicidal ester.
Agricultural Uses
Herbicide: Some uses are classified as U.S. Restricted
Use Pesticide (RUP). Diclofop-methyl is a selective
post-emergence herbicide used to control wild oats and
annual grassy weeds in grain and vegetable crops: alfalfa,
carrots, celery, box, field and french beans, barley,
wheat, brassicas, parsnips, peas, potatoes, rapeseed
(canola), soy beans, oilseed rape, onions, sugar beets and
lettuce.
Trade name
DICHLORDIPHENPROP®; HOELON®;
HOELON® 3EC; HOE-GRASS®; HOEGRASS®; HOE®
23408; ILOXAN®; ILLOXAN®; ONE SHOT®[C]
Mechanism of action
Selective, systemic with contact action. Acetyl CoA carboxylase inhibitor (ACCase) - distrupts fatty acid biosynthesis and lipid formation.
Environmental Fate
Biological. From the first-order biotic and abiotic rate constants of diclofop-methyl in estuarine water and sediment/water systems, the estimated biodegradation half-lives were 0.24–12.4 and 0.11–2.2 days, respectively (Walker et al., 1988).
Metabolic pathway
Two resistant biotypes of black-grass (Peldon A1 and
Lincs. E1 of Alopecurus myosuroides) exhibit
moderately enhanced metabolism of 14C-diclofop
methyl. Diclofop methyl is hydrolyzed to the
corresponding propionic acid which undergoes further
degradation to give polar metabolites. The amounts of
the metabolites depend on the metabolism activity of
the individual biotypes. In wheat, three isomeric
hydroxylated metabolites are identified in a major
metabolic pathway after acid hydrolysis of the
glucoside conjugates.
