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| | Carbaryl Basic information |
| | Carbaryl Chemical Properties |
| Melting point | 142-146 °C (lit.) | | Boiling point | 315°C | | density | d2020 1.232 | | vapor pressure | 2 (x 10-3 mmHg)at 40 °C (Meister, 1988) | | refractive index | 1.5300 (estimate) | | Fp | 202.7°C | | storage temp. | Sealed in dry,Room Temperature | | solubility | Moderately soluble in acetone, cyclohexanone, N,N-dimethylformamide (400–450 g/kg), and
isophorone (Windholz et al., 1983; Worthing and Hance, 1991) | | form | Crystalline | | pka | 12.02±0.46(Predicted) | | color | Crystals | | Water Solubility | Insoluble. 0.00826 g/100 mL | | Merck | 13,1794 | | BRN | 1875862 | | Henry's Law Constant | (x 10-5 atm?m3/mol):
1.27 at 20 °C (approximate - calculated from water solubility and vapor pressure) | | Exposure limits | NIOSH REL: TWA 5 mg/m3, IDLH 100 mg/m3; OSHA PEL: TWA 5
mg/m3; ACGIH TLV: TWA 5 mg/m3. | | Stability: | Stable. Combustible; incompatible with strong oxidizing agents. | | NIST Chemistry Reference | Carbaril(63-25-2) | | IARC | 3 (Vol. 12, Sup 7) 1987 | | EPA Substance Registry System | Carbaryl (63-25-2) |
| | Carbaryl Usage And Synthesis |
| Description | Carbaryl is a colourless to light tan or white or grey solid crystal depending on the purity of
the compound. The crystals are essentially odourless and stable to heat, light, and acids but
are not stable under alkaline conditions. It is non-corrosive to metals, packaging materials,
and application equipment. Carbaryl is classified as a general use pesticide (GUP). It is
sparingly soluble in water, but soluble in dimethylformamide, dimethyl sulfoxide, acetone,
cyclohexanone, isopropanol, and xylene. Carbaryl is a wide-spectrum carbamate insecticide,
which controls over 100 species of insects on citrus, fruit, cotton, forests, lawns, nuts,
ornamentals, shade trees, and other crops, as well as on poultry, livestock, and pets. It is
also used as a molluscicide and an acaricide. Carbaryl works whether it is ingested into
the stomach of the pest or absorbed through direct contact. It is available as bait, dusts,
wettable powders, granules, dispersions, and suspensions. | | Chemical Properties | Carbaryl is a colorless to light tan or white or gray, solid crystals depending on the purity of
the compound. The crystals are essentially odorless, and stable to heat, light, and acids, but
are not stable under alkaline conditions. It is non-corrosive to metals, packaging materials,
and application equipment. Carbaryl is classifi ed as a GUP. It is sparingly soluble in water,
but soluble in dimethylformamide, DMSO, acetone, cyclohexanone, isopropanol, and xylene.
Carbaryl is a wide-spectrum carbamate insecticide that controls over 100 species of insects
on citrus, fruit, cotton, forests, lawns, nuts, ornamentals, shade trees, and other crops, as well
as on poultry, livestock, and pets. It is also used as a molluscicide and an acaricide. Carbaryl
works whether it is ingested into the stomach of the pest or absorbed through direct contact.
It is available as bait, dusts, wettable powders, granules, dispersions, and suspensions | | Chemical Properties | colourless solid | | Physical properties | White to light tan crystals with a bleach-like type odor. At 40 °C, the average odor threshold
concentration and the lowest concentration at which an odor was detected were 280 and 37 μg/L,
respectively. At 25 °C, the average taste threshold concentration and the lowest concentration at
which a taste was detected were 140 and 44 μg/L, respectively (Young et al., 1996). | | Physical properties | White to light tan crystals with a bleach-like type odor. At 40°C, the average odor threshold
concentration and the lowest concentration at which an odor was detected were 280 and 37 μg/L,
respectively. At 25°C, the average taste threshold concentration and the lowest concentration at
which a taste was detected were 140 and 44 μg/L, respectively (Young et al., 1996). | | Uses | Contact insecticide used to control most insects on fruits, vegetables and ornamentals | | Uses | Carbaryl is a pesticide, an insecticide of the carbamate
group. It induced sensitization in a farmer. | | Uses | Contact insecticide. | | Uses | Cholinesterase inhibitor. Ectoparasiticide. | | Uses | Labelled Prifinium Bromide, a synthetic antispasmodic drug; parasympatholytic. Prifinium Bromide is used as a quartenary anticholinergic agent. | | Definition | ChEBI: A carbamate ester obtained by the formal condensation of 1-naphthol with methylcarbamic acid. | | Indications | Carbaryl (Sevin), a cholinesterase inhibitor insecticide, is used as a pediculicide
in the form of a shampoo. This product has an objectionable odor, but has some
ovicidal activity. It is an effective medication available in England and some
other countries but not in the United States. | | General Description | A white crystalline solid. Insoluble in water. Combustible, although difficult to ignite. Toxic by inhalation (dust, etc.). Produces toxic oxides of nitrogen during combustion. | | Air & Water Reactions | Slightly soluble in water. | | Reactivity Profile | Carbaryl is a carbamate ester. Carbamates are chemically similar to, but more reactive than amides. Like amides they form polymers such as polyurethane resins. Carbamates are incompatible with strong acids and bases, and especially incompatible with strong reducing agents such as hydrides. Flammable gaseous hydrogen is produced by the combination of active metals or nitrides with carbamates. Strongly oxidizing acids, peroxides, and hydroperoxides are incompatible with carbamates. Carbaryl is unstable in an alkaline media. . Carbaryl is incompatible with the following: Strong oxidizers, strongly alkaline pesticides . | | Hazard | Toxic by ingestion, inhalation, and skin
absorption; irritant. A reversible cholinesterase
inhibitor. Use may be restricted. Questionable car-
cinogen. Male reproductive and embryo damage.
| | Health Hazard | Acute oral toxicity — moderate in rats; dermal toxicity low to very low; oral LD50 value(rats); 250 mg/kg, skin LD50 value (rats);4000 mg/kg; toxic symptoms in humans —nausea, vomiting, diarrhea, abdominal cramps,miosis, lachrimation, excessive salivation,nasal discharge, sweating, cyanosis, muscletwitching, convulsions, and coma; acetylcholinesterase inhibitor; exposure limit: TLVTWA 5 mg/m3 (ACGIH, OSHA, and MSHA).
The poisoning effects from carbaryl takeplace very quickly, but lasts only for a shorttime. It is readily hydrolyzed to 1-naphtholwhich is excreted. Although its toxicity inhumans is relatively low, the compound canproduce strong effect on bees and aquaticspecies even in small quantities. | | Health Hazard | Highly toxic, may be fatal if inhaled, swallowed or absorbed through skin. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution. | | Health Hazard | Exposures to carbaryl cause a moderate to very toxic health disorder among workers.
Carbaryl produces adverse effects in humans by skin contact, inhalation, or ingestion. The
symptoms of acute toxicity are typical of the other carbamates. Direct contact of the skin or
eyes with moderate levels of this pesticide can cause burns. Inhalation or ingestion of very
large amounts can be toxic to the nervous and respiratory systems, resulting in nausea,
stomach cramps, diarrhea, and excessive salivation. Exposures to high concentrations of
carbaryl causes poisoning with symptoms such as excessive sweating, headache, weakness, giddiness, nausea, vomiting, stomach pains, blurred vision, slurred speech, muscle
twitching, incoordination, and convulsions. The effects of carbaryl on the nervous system
of rats, chickens, monkeys, and humans are primarily related to the inhibition of AChE
that under normal situations is transitory. The only documented fatality from carbaryl
was through intentional ingestion.
Laboratory studies have indicated that the acute oral toxicity (LD50) of carbaryl ranges
from 250 to 850 mg/kg in rats, and from 100 to 650 mg/kg in mice. The inhalation toxicity
(LC50) in rats is greater than 206 mg/L. Low doses of carbaryl cause minor skin and eye
irritation in rabbits. The acute dermal toxicity (LD50) of carbaryl to rabbits is measured as
greater than 2000 mg/kg. In a 90-day feeding study, carbaryl did not cause any signifi cant
adverse effects in rats. Carbaryl in high doses has caused no reproductive or fetal effects
in a long-term feeding study of rats.
Ingestion of carbaryl affected the lungs, kidneys, and liver of experimental animals.
Inhalation of carbaryl caused adverse effect to the lungs. High doses of carbaryl for a prolonged period caused nerve damage in rats and pigs. Several studies indicate that carbaryl
can affect the immune system in animals and insects.
The evidence for teratogenic effects due to chronic exposure is minimal in test animals.
Birth defects in rabbit and guinea pig offspring occurred only at dosage levels that were
highly toxic to the mother. | | Fire Hazard | Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Containers may explode when heated. Runoff may pollute waterways. | | Agricultural Uses | Insecticide, Nematicide, Plant growth regulator: Carbaryl is one of the most widely used insecticides in agriculture, professional turf management and ornamental production, as well as in residential pet, lawn, and garden markets. It controls over 100 species of insects that infect citrus, cotton, nuts, and forest and ornaments trees, as well as poultry and livestock. Carbaryl also is used as a mosquito adulticide. It is available in a variety of formulations bait, dust, wettable powders, granules, dispersions and suspensions. Washington State, for example, has a Special Local Needs registration to control burrowing shrimp in oyster beds. A U.S. EPA restricted Use Pesticide (RUP). Banned for use in EU countries. | | Trade name | ADIOS®; ARILAT®; ARILATE®; ARYLAM®; BERCEMA NMC50®; BUGMASTER®[C]; CAPROLIN®; CARBAMEC®; CARBAMINE®; CARBATOX®; CARBAVUR®; CARBOMATE®; CARPOLIN®; COMPOUND 7744®; CARYLDERM®; CRAG SEVIN®; CRUNCH®; DENAPON®; DICARBAM®; DYNA-CARBYL®; EXPERIMENTAL INSECTICIDE 7744®; GAMONIL®; GERMAIN'S®; HEXAVIN®; KARBASPRAY®; KARBATOX®; KARBOSEP®; MENAPHAM®; MICROCARB®; MUGAN®; MURVIN®; NAC®; NMC® 50; OMS29®; OMS 629®; OLTITOX®; PANAM®; POMEX®; PROSEVOR® 85; RAVYON®; SAVIT®[C]; SEPTENE®; SEFFEIN®; SEVIMOL®; SEVIN®; SEWIN®; SOK®; TERCYL®; THINSEC®; TORNADO®; TRICAR®; UNION CARBIDE 7,744®; VIOXAN® | | Contact allergens | Carbaryl is a pesticide and insecticide of the carbonate
group. It induced sensitization in a farmer. | | Safety Profile | Poison by ingestion,
intravenous, intraperitoneal, and possibly
other routes. Human systemic effects by
ingestion: sensory change involving
peripheral nerves and muscle weakness.
Experimental teratogenic and reproductive
effects. Questionable carcinogen with
experimental carcinogenic and tumorigenic
data. Human mutation data reported. An eye
and severe skin irritant. Absorbed by all
routes, although skin absorption is slow. No
accumulation in tissue. Symptoms include
blurred vision, headache, stomachache,
vomiting. Symptoms sirmlar to but less
severe than those due to parathion. A
reversible cholinesterase inhibitor. See also
CARBAMATES and ESTERS. When
heated to decomposition it emits toxic
fumes of NOx | | Potential Exposure | Carbaryl is a white or grayish, odorless,
crystalline solid; or various other forms including liquid
and paste. Molecular weight 5 201.24; boiling point 5
(decomposes below BP); freezing/melting point 5 142C;
vapor pressure 5, 4 3 1025 mmHg @ 25C; flash
point 5B200C. Hazard identification (based on NFPA-
704 M Rating System): Health 3, flammability 1, reactivity
0. Practically insoluble in water; solubility 5 0.02 g/L @
30C | | Carcinogenicity | Carbaryl is not considered to be
genotoxic. | | Environmental Fate | Biological. Fourteen soil fungi metabolized methyl-14C-labeled carbaryl via hydroxylation to 1-naphthyl-N-hydroxymethylcarbamate, 4-hydroxy-1-naphthylmethylcarbamate and 5-hydroxy-1-naphthylmethylcarbamate (Bollag and Liu, 1972). Carbaryl was degraded by a culture of Aspergillus terreus to 1-naphthylcarbamate. The half-life was 8 days (Liu and Bollag, 1971a).
Various microorganisms isolated from soil hydrolyzed carbaryl to 1-napthol. For example, Fusarium solani degraded carbaryl 82% after 12 days at a temperature of 26–28°C (Bollag and Liu, 1971).
In a small watershed, carbaryl was applied to corn seed farrows at a rate of 5.03 kg/ha active ingredient. Carbaryl was stable up to 166 days, but after 135 days, 95% had disappeared. The long lag time suggests that carbaryl degradation was primarily due to microbial degradation (Caro et al., 1974).
Soil. The rate of hydrolysis of carbaryl in flooded soil increased when the soil was pretreated with the hydrolysis product, 1-naphthol (Rajagopal et al., 1986). Carbaryl is hydrolyzed in both flooded and nonflooded soils but the rate is slightly higher under flooded conditions (Rajagopal et al., 1983). When 14C-carbonyl-labeled carbaryl (200 ppm) was added to five different soils and incubated at 25°C for 32 days, evolution of 14Ccarbon dioxide varied from 2.2–37.4% (Kazano et al., 1972). Metabolites identified in soil included 1-naphthol (hydrolysis product) (Sud et al., 1972; Ramanand et al., 1988a), hydroquinone, catechol, pyruvate (Sud et al., 1972), coumarin, carbon dioxide (Kazano et al., 1972), 1-naphthylcarbamate, 1-naphthyl N-hydroxymethylcarbamate, 5-hydroxy-1-naphthylmethylcarbamate, 4-hydroxy-1-naphthylmethylcarbamate and 1-naphthyl hydroxymethylcarbamate (Liu and Bollag, 1971, 1971a). 1-Naphthol was readily degraded by soil microorganisms (Sanborn et al., 1977).
When carbaryl was applied to soil at a rate of 1,000 L/ha, more than 50% remained in the upper 5 cm (Meyers et al., 1970). The half-lives of carbaryl in a sandy loam, clay loam and an organic amended soil under non-sterile conditions were 96–1,462, 211–2,139 and 51–4,846 days, respectively, while under sterile conditions the half-lives were 67–5,923, 84–9,704 and 126–4,836, respectively (Schoen and Winterlin, 1987).
Liu and Bollag (1971) reported that the fungus Gliocladium roseum degraded carbaryl to 1-naphthyl N-hydroxymethylcarbamate, 4-hydroxy-1-naphthylmethylcarbamate and 1- naphthylhydroxymethylcarbamate.
Sud et al. (1972) discovered that a strain of Achromobacter sp. utilized carbaryl as the sole source of carbon in a salt medium. The organism grew on the degradation products 1-naphthol, hydroquinone and catechol. 1-Naphthol, a metabolite of carbaryl in soil, was recalcitrant to further degradation by a bacterium tentatively identified as an Arthrobacter sp. under anaerobic conditions (Ramanand et al., 1988a). Carbaryl or its metabolite 1- naphthol at normal and ten times the field application rate had no effect on the growth of Rhizobium sp. or Azotobacter chroococcum (Kale et al., 1989). The half-lives for carbaryl under flooded and nonflooded conditions were 13–14 and 23–28 days, respectively (Venkateswarlu et al., 1980).
Rajagopal et al. (1984) identified the following degradates of carbaryl in soil and in microbial cultures: 5,6-dihydrodihydroxy carbaryl, 2-hydroxy carbaryl, 4-hydroxy carbaryl, 5-hydroxy carbaryl, 1-naphthol, N-hydroxymethyl carbaryl, 1-naphthyl carbamate, 1,2-dihydroxynaph-thalene, 1,4-dihydroxynaphthalene, o-coumaric acid, o-hydroxybenzalpyruvate, 1,4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, coumarin, γ-hydroxy-γ-ohydroxyphenyl-α-oxobutyrate, 4-hydroxy-1-tetralone, 3,4-di-hydroxy-1-tetralone, pyruvic acid, salicylaldehyde, salicylic acid, phenol, hydroquinone, catechol, carbon dioxide and water. When carbaryl was incubated at room temperature in a mineral salts medium by soil-enrichment cultures for 30 days, 26.8 and 31.5% of the applied insecticide remained in flooded and nonflooded soils, respectively (Rajagopal et al., 1984a). A Bacillus sp. and the enrichment cultures both degraded carbaryl to 1-naphthol. Mineralization to carbon dioxide was negligible (Rajagopal et al., 1984a). | | Metabolic pathway | The metabolism of carbaryl has been extensively reviewed many times
and so original research papers are not generally quoted. Pathways for
carbaryl include hydroxylation of the aromatic ring and the methyl group,
carbamate ester hydrolysis and conjugation. The metabolism of carbaryl
has been extensively reviewed by Schlagbauer and Schlagbauer (1972),
Fukuto (1972), Kuhr and Dorough (1976), Mount and Oehme (1981) and
by the WHO (1994). Metabolism in man was reviewed by Hutson (1981)
and in economic animals by Akhtar (1985). | | Metabolism | Carbaryl undergoes hydrolysis and
ring oxidation in soils. The major metabolite in a number
of studies was 1-naphthol. Metabolites also included
4-hydroxycarbaryl and 5-hydroxycarbaryl. In mammals,
the major metabolite is 1-naphthol. This is eliminated in urine and feces, together with the glucuronic acid conjugate.
Aromatic ring hydroxylation at the 3-, 4-, 5-, or 6-
positions also occurs as does hydroxylation at the N-methyl
group. | | Shipping | UN2757 Carbamate pesticides, solid, toxic,
Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN
2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1;
Labels: 6.1-Poisonous materials, Technical Name Required | | Toxicity evaluation | Carbaryl is soluble in organic solvents (e.g., dimethyl formamide,
acetone) and is moderately soluble in water (32 mg l-1
solubility at 20°C). The calculated Henry’s law constant of
0.000000003 atm m3 mol l-1 indicates that surface water volatilization
is unlikely an important fate process. The estimated
half-life for reacting with airborne photochemically generated
hydroxyl radicals is 12.6 h. Photolysis produces naphthoquinone
products.
Carbaryl undergoes abiotic hydrolysis, photodegradation,
and biotic degradation in soil and water. Depending on soil
type and climate, its soil persistence varies from 13 days to
2 years. Half-lives in canal and river waters vary from 4 to
30 days, hydrolysis rate is greater with increasing temperature
and alkalinity. Carbaryl can persist for years under acidic
environments. The estimated log Koc of 1.87–2.46 indicates
moderate adsorption to soil and the potential for groundwater
leaching. | | Degradation | Carbaryl is stable in neutral and weakly acidic media but hydrolysed
under basic conditions (PM).
Hydrolysis in natural waters is mostly chemical, usually with a half-life
of a few days or less. Carbaryl undergoes base-catalysed hydrolysis to
form 1-naphthol(2) and N-methylcarbamic acid (3) which decomposes to
methylamine and CO2 (see Scheme 1). No other degradation product
accounted for more than 2% of the applied dose and no volatile products
were detected during hydrolysis (WHO, 1994). Carbaryl is not rapidly
photodegraded in the field. In basic solutions exposed to light, the dissociated
form of 1-naphthol (2) (1-naphthoxide ion) was transformed to
2-hydroxy-1,4-naphthoquinone (4) as confirmed by MS (Kuhr and
Dorough, 1976). Photodecomposition accounted for some loss of carbaryl
in clear surface waters exposed to sunlight for long periods but this
was not a major route of degradation. Cleavage of the ester bond was the
main photo-reaction, but in organic solvents other reactions can occur
to give small amounts of naphthamides, naphthalene and β-naphthyl-1-naphthol.
l-Naphthol (2) was photodecomposed faster than carbaryl
(WHO, 1994).
An aqueous photolysis study was conducted under conditions relevant
to decontamination rather than to the natural environment. Aqueous solutions
of carbaryl containing a dispersion of TiO2 were irradiated with a
xenon lamp, with a cut-off filter at 340 nm, at 55 °C. Solutions were
extracted and analysed by HPLC or GC-MS methods. Parent carbaryl
degraded within 30 minutes at pH 3, 6 or 9. It was suggested that the
initial step was attack by hydroxyl radical. The N-methylcarbamoyl
moiety was cleaved and hence no carbamate products were identified.
Pathways involved hydroxylation of the ring and oxidation of dihydroxy
derivatives to form quinones (see Scheme 1). Intermediates identified
included 1,2-, 1,3- and 1,4-dihydroxybenzenes (5, 6 and 7), 1,2,3-
trihydroxybenzene (8), dihydroxynaphthalene (9), 1,4-naphthaquinone
(10), 2- and 5-hydroxynaphthaquinone (4 and 11), other hydroxynaphtha-lenediones (12) and a small proportion of 1,3-indandione (13)(Pramauro et al., 1997). | | Incompatibilities | Contact with strong oxidizers can cause
fire and explosions.
| | Waste Disposal | Dissolve or mix the material
with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal,
state, and local environmental regulations must be
observed. Submit to alkaline hydrolysis before disposal. |
| | Carbaryl Preparation Products And Raw materials |
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