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| | Chlorfenvinfos Basic information |
| | Chlorfenvinfos Chemical Properties |
| Melting point | -23--19 °C | | Boiling point | bp0.001 120°; bp0.5 167-170° | | density | 1.36 g/cm3 | | vapor pressure | 0.53 Pa | | refractive index | nD25 1.5272 | | Fp | 100 °C | | storage temp. | 2-8°C | | solubility | Chloroform (Slightly), Methanol (Slightly) | | form | Liquid | | Water Solubility | Insoluble | | Merck | 13,2105 | | BRN | 8712900 | | CAS DataBase Reference | 470-90-6(CAS DataBase Reference) | | NIST Chemistry Reference | Clofenvinfos(470-90-6) | | EPA Substance Registry System | Chlorfenvinphos (470-90-6) |
| | Chlorfenvinfos Usage And Synthesis |
| Chemical Properties | Chlorfenvinphos is a nonflammable, yellow or
amber liquid with a mild odor. | | Uses | Insecticide; acaricide. | | Uses | From 1963 until the early 1990s, chlorfenvinphos was extensively
used in veterinary products (dip, dust, and collars) for
flea and tick control on pets and domestic animals, and in dairy
barns, milk rooms, poultry houses, and other animal buildings.
Agriculturally, it was used on potatoes, rice, and maize, and for
control of soil insects and nematodes. All uses were canceled in
the United States in 1991 and phased out in EU in 2006.
Chlorfenvinphos continues to be used in Australia and New
Zealand in veterinary products for combating ectoparasites on
cattle and sheep. | | Uses | Chlorfenvinphos is used to control soil insects such as root worms
on vegetables, bulb flies in wheat and maize and phorid and sciarid flies
in mushrooms. It is also used to control Colorado beetles on potatoes,
scale insects and mite eggs in citrus and stern borers and hoppers on rice.
Other uses are the control of mosquitoes and animal ectoparasites as a
sheep and cattle dip. | | Preparation | Chlorfenvinphos is synthesized by the Perkow reaction
of triethyl phosphite with 2,4-α,α-tetrachloroacetophenone.
Technical product is an E/Z isomer mixture
with an E : Z ratio of 1 : 8–9 and an amber liquid,
bp 167–170 ?C/0.5 mm Hg, vp 1 mPa (25 ?C), sparingly
soluble in water (145 mg/L), and miscible with most
common organic solvents such as acetone and aromatic
hydrocarbons. Log Kow = 3.85. It is hydrolyzed slowly in
slightly alkaline aqueous solutions and rapidly in strongly
alkaline solutions; DT50 values are >700 h (pH 1.1, 38 ?C),
>400 h (pH 9.1, 38 ?C), and 1.28 h (pH 13, 20 ?C). | | General Description | Amber-colored liquid with a mild chemical odor. Used for control of ticks, flies, lice, and mites on cattle and for blowfly, lice, ked, and itchmite on sheep. Controls fleas and mites on dogs; not used on cats. Applied on organic wastes and breeding places of fly larvae. Also used as a foliage insecticide for potatoes, rice, maize, and sugar cane. Used to control soil insects. | | Air & Water Reactions | Slightly soluble in water. | | Reactivity Profile | Organophosphates, such as Chlorfenvinfos, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides. | | Hazard | A cholinesterase inhibitor. | | Health Hazard | Highly toxic by all routes of exposure; however, more toxic in rat than in mouse and rabbit; cholinesterase inhibitor; exhibits acute,delayed, and chronic poisoning; toxic symptoms range from headache, twitching, salivation, blurred vision, and lacrimation togastrointestinal effects and respiratory paralysis; in humans permeation through skin at adosage level of 10–15 mg/kg may manifesttoxic effect.
LD50 oral (rat): 10 mg/kg
LD50 skin (rabbit): 300 mg/kg
LC50 inhalation (rat): 50 mg/m3 /4 h. | | Health Hazard | Acute: cholinesterase inhibitor which affects central nervous system. Severe illness or death possible. Convulsions or coma and death. | | Fire Hazard | (Non-Specific -- Organophosphorus Pesticide, Liquid, n.o.s.) Chlorfenvinfos may burn but does not ignite readily. Container may explode in heat of fire. Fire and runoff from fire control water may produce irritating or poisonous gases. Avoid iron, steel, and brass. Stable when stored in glass or polyethylene lined containers. Avoid alkaline aqueous solutions. | | Safety Profile | Poison by ingestion,
skin contact, intraperitoneal, subcutaneous,
and intravenous routes. Human systemic
effects by skin contact: unspecified blood
system effects. Mutation data reported. A
cholinesterase inhibitor. An insecticide. See
also PARATHION. When heated to
decomposition it emits very toxic fumes of
Cland POx. | | Potential Exposure | Used as a soil insecticide for root
maggots, rootworms, and cutworms. Those engaged in the
production, formulation, and application of this insecticide. | | Environmental Fate | The mechanism of toxicity of chlorfenvinphos is related to its
binding and inhibition of the serine hydrolase AChE. In the
nervous system, AChE hydrolyzes the neurotransmitter acetylcholine,
thereby terminating its synaptic action. AChE inhibition
increases the availability of acetylcholine at the neural
synapse, leading to cholinergic overstimulation, autonomic
and neuromuscular dysfunction, and at higher levels, resulting
in coma and death. Major metabolites of chlorfenvinphos do
not inhibit ChE. Chlorfenvinphos inhibits butyrylcholinesterase
which may function as a molecular scavenger for anti-ChE
compounds in the blood or substitute for AChE where it is low.
The stress responses to acute exposure of chlorfenvinphos
are evidenced in rats by rapidly increased plasma corticosterone
concentrations and a prolonged reduced sensitivity to psychostimulants
such as amphetamine. These effects were
attributed to the hyperactivity of the cholinergic system from
ChE inhibition, leading to persistent alterations of the brain
cholinergic–dopaminergic balance.
Other potentially more sensitive non-ChE targets that may
influence the overall toxicity of chlorfenvinphos include lipid
metabolism, oxidative stress, aromatic amino acid transferases,
and cytotoxicity. Chlorfenvinphos may act via central noradrenergic
mechanisms to induce hypotension by accelerating the
noradrenaline turnover in the brain. Chlorfenvinphos induces
hepatic CYPs. | | Metabolic pathway | Chlorfenvinphos is a chlorovinyl organophosphate insecticide and
the commercial material consists of an E/Z isomer mixture with a
Z:E ratio of 8-9:1. The Z-isomer is usually the more insecticidal to
most species of insect. Metabolism studies have generally used a
stereochemical mixture; however, there is evidence that the E-isomer is
photoisomerised to the more stable 2-isomer in the field. The breakdown
of chlorfenvinphos has been extensively studied in soil, plants
and mammals. The major routes of detoxification are by de-ethylation
and hydrolysis and are similar in principle to those of related
vinyl phosphates. The products of dealkylation and hydrolysis are
desethylchlorfenvinphos and 2,2’,4’-trichloroacetophenone plus dimethyl
phosphate, respectively. Further metabolism of the chloroacetophenone
moiety then leads, via reduction or eventual hydrolysis
of the side-chain chlorine substituent, to the formation of 1-(2,4-
dichlophenyl)ethane-l,2-diol and 1-(2,4-dichlorophenyl)ethan-1-ol which
are conjugated with glucose or glucuronic acid as the ultimate metabolites.
Oxidation of the β carbon atom to give 2,4-dichloromandelic acid
followed by decarboxylation gives 2,4-dichlorobenzoic acid which is
conjugated with glycine in some mammals as the final metabolite.
The 2,4dichlorophenyl moiety usually remains intact during metabolism
although hydrolysis of ring chlorine has been reported in a soil
degradation study. Metabolism studies have been reviewed by Beynon
et al. (1973) and by the Pesticide Safety Directorate evaluation on
chlorfenvinphos (PSD, 1994). | | Shipping | UN3018 Organophosphorus pesticides, liquid,
toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials. | | Toxicity evaluation | The toxicity is particularly high
to rats (acute oral LD50 10–40 mg/kg) but is much lower
to other mammals (acute oral LD50 for mice 117–200,
rabbits 300–1,000, dogs >12, 000 mg/kg). Inhalation LC50
(4 h) for rats is about 0.05 mg/L air. NOEL (2 yr) for
rats and dogs is 1 mg/kg diet (0.05 mg/kg/d). ADI is
0.5 μg/kg b.w.
The selective toxicity of chlorfenvinphos to rats
is attributed to the poor degradative activity of rat
liver microsomal enzymes. In other mammals, liver
microsomal mfo catalyzes the detoxification of the
insecticide through oxidative deethylation to give 2-
chloro-1-(2,4-dichlorophenyl)vinyl hydrogen phosphate.
Ultimate metabolites include the glucuronides of 2,4-
dichlorophenylethanediol and 1-(2,4-dichlorophenyl)ethanol
and N-(2,4-dichlorobenzoyl)glycine. In soils, chlorfenvinphos
is gradually decomposed to form α-dichlorophenylethanol,
dichloroacetophenone, diethyl hydrogen phosphate,
and desethyl chlorfenvinphos. | | Degradation | Chlorfenvinphos is hydrolysed slowly in neutral, acidic and slightly
alkaline aqueous solutions but hydrolysed rapidly in strongly alkaline
solutions (PM). The E and Z stereoisomers are capable of interconversion
by photoisomerisation (Beynon and Wright, 1967). | | Incompatibilities | Incompatible 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. Strong oxidizers may
cause release of toxic phosphorus oxides. Organophosphates,
in the presence of strong reducing agents such as hydrides,
may form highly toxic and flammable phosphine gas. Keep
away from alkaline materials. May be corrosive to metals in
the presence of moisture. | | Waste Disposal | Destruction by alkali hydrolysis or incineration. 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. |
| | Chlorfenvinfos Preparation Products And Raw materials |
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