2921-88-2 Usage
Description
Chlorpyrifos is a broad-spectrum organophosphate insecticide, acaricide, and miticide used primarily for the control of foliage and soil-borne insect pests in various food and feed crops. It is a white crystalline or irregularly flaked solid with a mild sulfur odor and is not soluble in water. Chlorpyrifos acts by suppressing the nervous system of insects through the inhibition of acetylcholinesterase. It is sold under trade names such as Dursban, Empire 20, Equity, and Whitmire PT 270 and has been widely used around the world since its first registration in 1965.
Uses
1. Agricultural Uses:
Chlorpyrifos is used as an insecticide, nematicide, and miticide for a wide variety of crops, including fruits, vegetables, ornamentals, and forestry. It is effective in controlling pests such as cutworms, corn rootworms, cockroaches, grubs, flea beetles, flies, termites, fire ants, and lice. It is applied to grain, cotton, field, fruit, nut, and vegetable crops, as well as on lawns and ornamental plants.
2. Residential and Commercial Uses:
Chlorpyrifos is used to control household pests, mosquitoes, and pests in animal houses. It is an active ingredient in many commercial insecticides such as Dursban and Lorsban. It is also used for direct application on sheep and turkeys, horse site treatment, dog kennels, domestic dwellings, farm buildings, storage bins, and commercial establishments.
3. Non-Agricultural Applications:
Chlorpyrifos is used in golf courses, turf, greenhouses, and no-structural wood treatment. It can also be used as a mosquito adulticide and in roach and ant bait stations in child-resistant packaging.
4. Chemical Properties and Formulations:
Chlorpyrifos is available in various formulations, including emulsifiable concentrate, dust, granular wettable powder, microcapsule, pellet, and sprays. It is insoluble in water but soluble in organic solvents such as benzene, acetone, chloroform, carbon disulfide, diethyl ether, xylene, methylene chloride, and methanol.
5. Regulatory Status:
The U.S. EPA has classified chlorpyrifos as a General-Use Pesticide (GUP) and has imposed residential use limitations in the United States, Canada, Australia, and the European Union due to concerns regarding toxicity to the developing nervous system. However, it continues to be used in large quantities to control crop damage worldwide, particularly in developing countries where excessive agricultural application and lack of protective devices can result in numerous fatalities annually.
References
https://en.wikipedia.org/wiki/Chlorpyrifos
https://www.epa.gov/ingredients-used-pesticide-products/chlorpyrifos
Air & Water Reactions
Insoluble in water. Chlorpyrifos reacts with water and most reactive hydrogen compounds. The rate of hydrolysis in water increases with pH, with temperature and with the presence of copper and possibly other metals that can form chelates.
Reactivity Profile
Chlorpyrifos is sensitive to heat and is decomposed by moisture. Chlorpyrifos is hydrolyzed by strong alkalis. Chlorpyrifos is corrosive to copper and brass. Chlorpyrifos is also corrosive to copper alloys. Chlorpyrifos reacts with water and most reactive hydrogen compounds. The rate of hydrolysis in water increases with pH, with temperature and with the presence of copper and possibly other metals that can form chelates.
Health Hazard
Exposures to chlorpyrifos cause adverse health effects and poisoning. The symptoms
include, but are not limited to, headache, dizziness, respiratory problems, muscular and
joint pains, numbness, tingling sensations, incoordination, tremor, nausea, abdominal
cramps, vomiting, sweating, blurred vision, respiratory depression, slow heart beat, nervousness, weakness, cramps, diarrhea, chest pain, pin-point pupils, tearing, salivation,
clear nasal discharge and sputum, muscle twitching, and in severe poisonings convulsions, coma, and death. Exposures to chlorpyrifos cause adverse effects to the nervous
system. The effects include phosphorylation of the active site, disturbance in the activity of the acetylcholinesterase (AChE) enzyme (inactivity). AChE enzyme is necessary to stop
the transmission of the chemical neurotransmitter.
In occupational workers, high concentrations of chlorpyrifos cause poisoning with
symptoms of unconsciousness, convulsions and/or fatal injury. Persons with respiratory ailments and disturbed liver function are known to be at increased health risk.
Also, repeated exposures to chlorpyrifos have been reported to cause disturbances in
the process of brain development.
Health Hazard
Cholinesterase inhibitor; heavy exposurecan produce acute, delayed, and chroniceffect; exhibits low to moderate toxicity inexperimental animals when administered byoral and dermal routes; however, severity ofeffects varies with species; highly toxic tobirds; ingestion of 1.5–2 g would probablyresult in onset of cholinergic effects in adulthumans.LD50 oral (rat): ～150 mg/kgLD50 oral (rabbit): 1000 mg/kgLD50 oral (wild bird): 5 mg/kgLD50 oral (chicken): 25 mg/kgLD50 skin (rat): ～200 mg/kgLD50 skin (rabbit): 2000 mg/kg.
Fire Hazard
Combustible material: may burn but does not ignite readily. Containers may explode when heated. Runoff may pollute waterways. Substance may be transported in a molten form.
Flammability and Explosibility
Notclassified
Trade name
(Note: EPA Office of Pesticide Programs
lists 2135 products, both active and past-registered)
ALUDOR?; BAR 500 EC?; BRODAN?; CHLORBAN?;
CHLORPIRIFOS 480 CE MILENIA?; CHOIR?;
COROBAN?; CURIGNA?; CYREN?; DETMOL U. A. ?;
DORSAN?; DORSAN?-C; DOWCO? 179; DURSBAN?;
EF 121?; EMPIRE?; ERADEX?; GLOBAL CRAWLING
INSECT BAIT?; KENSBAN?; LORSBAN?; MURPHY
SUPER ROOT GUARD?; PAQEANT?; PILOT?;
PYRINEX?); SCOUT?; SPANNIT?; STIPEND;
TALON?; TAFABAN?; TERIAL?; TWINSPAN?
Safety Profile
Poison by ingestion,
intraperitoneal, skin contact, and inhalation
routes. Human systemic effects by ingestion:
paresthesia, muscle weakness, coma.
Experimental reproductive effects:
developmental toxicity. Mutation data
reported. When heated to decomposition it
emits very toxic fumes of Cl-, NOx POx
and SOx
Potential Exposure
A potential danger to those involved in the manufacture, formulation, and application of this insecticide.
Carcinogenicity
Some recent studies have
reported associations between chlorpyrifos exposure and
increased risk for cancer for farm workers participating in
the Agricultural Health Study. Specifically, increased risk for
glioma and rectal cancer has been associated with chlorpyrifos
exposure . Chlorpyrifos was also one pesticide
associated with trends toward higher incidence of lung
cancer through 2001 . For all cancers though, follow-
up periods are short and exposures are based on recall so
results may be unreliable.
Environmental Fate
Biological. From the first-order biotic and abiotic rate constants of chlorpyrifos in
estuarine water and sediment/water systems, the estimated biodegradation half-lives were
3.5–41 and 11.9–51.4 days, respectively (Walker et al., 1988)Soil. Hydrolyzes in soil to 3,5,6-trichloro-2-pyridinol (Somasundaram et al., 1991).
The half-lives in a silt loam and clay loam were 12 and 4 weeks, respectively (Getzin,
1981). In another study, Getzin (1981a) reported the hydrolysis half-livesLeoni et al. (1981) reported that the major degradation product of chlorpyrifos in soil
is 3,5,6-trichloro-2-pyridinol. The major factors affecting the rate of degradation include
chemical hydrolysis in moist soils, clay-catalyzed hydrolysis on dry soil sPlant. The half-life of chlorpyrifos in Bermuda grasses was 2.9 days (Leuck et al.,
1975). The concentration and the formulation of application of chlorpyrifos will determine
the rate of evaporation from leaf surfaces. Reported foliar half-lives on tomato, orange and
cotton leaves were 15–139, 1.4–96 and 5.5–57 hours, respectively (Veierov et al., 1988).
Dislodgable residues of chlorpyrifos on cotton leaf 0, 24, 48, 72 and 96 hours after
application (1.1 kg/ha) were 3.64, 0.13, 0.071, 0.055 and 0.034 μg/m2, respectively (Buck
et al., 1980)Surface Water. In an estuary, the half-life of chlorpyrifos was 24 days (Schimmel et
al., 1983).
Metabolic pathway
The metaboic fate of chlorpyrifos in soil, plants and animals is similar,
with oxidative dealkylation or hydrolysis to diethyl phosphorothioate
and 3,5,6-trichloro-2-pyridinol being the major route of detoxification.
The latter metabolite is conjugated as the glycosides or glucuronides in
plants and animals. De-ethylation is not a major route of detoxification in
mammals. Activation by desulfuration to the active acetylcholinesterase
inhibitor, chlorpyrifos oxon, occurs in both animals and plants but the
compound is often not detected owing to its rapid rate of hydrolysis.
Dechlorination of the chloropyridine ring also occurs in the environment,
principally by photolysis.
Shipping
UN2783 Organo phosphorus pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN3018 Organophosphorus pesticides, liquid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.
Degradation
Chlorpyrifos is hydrolysed in acid, neutral and alkaline solution (PM).
In neutral solution (approximately pH 7 and 25 °C) the DT50 for decomposition
was variously reported as between 29 and 72 days. DT50s in
buffered solutions at pH 4.7,6.9 and 8.1 were reported as being 62.7,35.3
and 22.9 days respectively (Racke, 1993). Hydrolysis is much faster
in alkaline solutions and the DT50 at pH 11 was reported as 0.5 day
(Macalady and Wolfe, 1983). The mechanisms of hydrolysis and nature of
the products are pH-dependent. As has been found with many organophosphates,
O-dealkylation predominates at acid and neutral pH values
and in alkaline solution the main mechanism is cleavage of the P-O-aryl
bond. Macalady and Wolfe (1983) showed that in buffered aqueous polar
solvent mixtures at pH 9.7 to 12.9 the only products were 3,5,6-trichloro-
2-pyridinol(2) and diethyl phosphorothioate (3). In near neutral solution
(pH 7.68) the main products were desethylchlorpyrifos (4) and ethanol
with lesser amounts of 2 and 3. The mechanism for base-catalysed
hydrolysis is via SN2 hydroxide attack on phosphorus, whereas under
acid and neutral conditions the nucleophile is water and the rate is pH-independent
with a half-life of 72.1 days and 72.9 days being reported at
pH 5 and 7 respectively. Chlorpyrifos oxon (10, Scheme 2) was much
more easily hydrolysed (Kenaga, 1971). Pathways for the hydrolytic
degradation of chlorpyrifos in acid and base solution are shown in
Scheme 1.
Toxicity evaluation
Chlorpyrifos undergoes abiotic hydrolysis, photodegradation,
and biotic degradation in soil and water. Depending on
the soil type and climate, its soil persistence varies from 2 weeks
to over 1 year. Microbial degradation is indicated by the shorter
half-lives in natural soils than sterile soils. Chemical hydrolysis
produces O-ethyl-O-3,5,6-trichloro-2-pyridyl phosphorothioate
or 3,5,6-trichloro-2-pyridinol (TCP) and phosphorthioic acid
at alkaline conditions. Half-lives in river and well waters vary
from 4.8 to 38 days, with the rate of hydrolysis increasing
with temperature and alkalinity. The estimated Log Koc of
3.73 predicts strong adsorption to soil and resist leaching
to groundwater. Chlorpyrifos can persist indoors for several
months.
Oxidation of chlorpyrifos to its more toxic metabolite chlorpyrifos
oxon could occur through photolysis, aerobic metabolism,
and chlorination. Water chlorination is the major route
of chlorpyrifos oxon formation. It is subsequently rapidly hydrolyzed toTCP.TCP and its glucuronide conjugates have been
detected in fish tissues. The measured Kow of 4.8 indicates
a potential for bioaccumulation in aquatic and terrestrial food
chains.
Incompatibilities
Above 130°C this chemical may undergo violent exothermic decomposition. The substance decomposes on heating at approximately 160°C and on burning, producing toxic and corrosive fumes including hydrogen chloride, nitrogen oxides; phosphorous oxides, sulfur oxides. Reacts with strong acids; strong bases; causing hydrolysis. Attacks copper and brass. Contact with oxidizers may cause the release of phosphorous oxides. Contact with strong reducing agents, such as hydrides, may cause the formation of flammable and toxic phosphine gas.
Waste Disposal
This compound is 50% hydrolyzed in aqueous MeOH solution at pH 6 in 1930 days; and in 7.2 days at pH 9.96. Spray mixtures of <1% concentration are destroyed with an excess of 5.25% sodium hypochlorite in <30 minutes @ 100°C; and in 24 hours @ 30°C. Concentrated (61.5%) mixtures are essentially destroyed by treatment with 100:1 volumes of the above sodium hypochlorite solution and steam in 10 minutes. In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.
Precautions
Occupational workers should be careful during handling and use of chlorpyrifos. The
workplace should have adequate washing facilities at all times and close to the site of
handling and use. Eating, drinking, and smoking should be prohibited during handling
and before washing after handling. Containers should be kept away from foodstuffs,
animal feed and their containers, and out of reach of children.
Check Digit Verification of cas no
The CAS Registry Mumber 2921-88-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 2,9,2 and 1 respectively; the second part has 2 digits, 8 and 8 respectively.
Calculate Digit Verification of CAS Registry Number 2921-88:
(6*2)+(5*9)+(4*2)+(3*1)+(2*8)+(1*8)=92
92 % 10 = 2
So 2921-88-2 is a valid CAS Registry Number.
InChI:InChI=1/C9H11Cl3NO3PS/c1-3-15-17(14,16-4-2)18-9-7(11)5-6(10)8(12)13-9/h5H,3-4H2,1-2H3
2921-88-2Relevant articles and documents
Reinvestigation of phase-transfer-catalyzed chlorpyrifos synthesis
Fakhraian,Moghimi,Ghadiri,Dehnavi,Sadeghi
, p. 680 - 684 (2004)
Production of chlorpyrifos via the phase-transfer-catalyzed reaction of 0,0-diethylphosphorochloridothioate and the sodium salt of 3,5,6- trichloropyridin-2-ol was reinvestigated. The formation of sulfotep (the major byproduct) and the yield are influence
Chlorpyrifos production method
-
Paragraph 0033-0050, (2018/05/01)
Provided is a chlorpyrifos production method. Trichloro-acetic chloride is used as a starting raw material, an intermediate 3,3,5,6-tetrachloro-4,5-dihydropyridine-2(3H)-ketone is synthesized throughaddition and cyclization reaction, and then chlorpyrifos is synthesized through alkaline hydrolysis, condensation reaction and one-pot process reaction. The 3,5,6-trichloropyridine-2-sodium phenolatefiltering link after alkaline hydrolysis reaction is omitted, the chlorpyrifos is synthesized through a one-pot process, and operation steps are simplified. A dual-solvent method is adopted for condensation reaction, hydrolysis of O,O-diethyl thiophosphoryl chloride and generation of sulfotep can be effectively inhibited, the content of the synthesized chlorpyrifos product is 97% or above, and thetotal yield is 83% or above. Produced wastewater is greatly decreased, the total wastewater discharging amount is reduced by about 50% compared with an existing process, and the chlorpyrifos production method is suitable for industrial production.
Concentrates of organophosphorous insecticides
-
, (2008/06/13)
A low volatile organic compound co-solvent system is disclosed for preparing emulsion concentrates of low melting organophosphorous insecticides wherein the bioefficacy of the insecticide active is significantly enhanced. The co-solvent system comprises a water-soluble ethoxylated fatty acid/rosin acid-nonionic surfactant composition.
