Carbaryl

Last updated
Carbaryl
Carbaryl-2D-skeletal.png
Carbaryl-3D-balls.png
Names
Preferred IUPAC name
Naphthalen-1-yl methylcarbamate
Other names
Sevin (Generic trademark)
α-Naphthyl N-methylcarbamate
1-Naphthyl methylcarbamate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.505 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 200-555-0
KEGG
PubChem CID
RTECS number
  • FC5950000
UNII
UN number 2757
  • InChI=1S/C12H11NO2/c1-13-12(14)15-11-8-4-6-9-5-2-3-7-10(9)11/h2-8H,1H3,(H,13,14) Yes check.svgY
    Key: CVXBEEMKQHEXEN-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C12H11NO2/c1-13-12(14)15-11-8-4-6-9-5-2-3-7-10(9)11/h2-8H,1H3,(H,13,14)
    Key: CVXBEEMKQHEXEN-UHFFFAOYAZ
  • CNC(=O)Oc1c2ccccc2ccc1
Properties
C12H11NO2
Molar mass 201.225 g·mol−1
AppearanceColorless crystalline solid
Density 1.2 g/cm3
Melting point 142 °C (288 °F; 415 K)
Boiling point decomposes
very low (0.01% at 20°C) [1]
Pharmacology
QP53AE01 ( WHO )
Hazards
GHS labelling:
GHS-pictogram-skull.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Danger
H301, H302, H332, H351, H410
P201, P202, P261, P264, P270, P271, P273, P281, P301+P310, P301+P312, P304+P312, P304+P340, P308+P313, P312, P321, P330, P391, P405, P501
Flash point 193-202 [1]
Lethal dose or concentration (LD, LC):
710 mg/kg (rabbit, oral)
250 mg/kg (guinea pig, oral)
850 mg/kg (rat, oral)
759 mg/kg (dog, oral)
500 mg/kg (rat, oral)
150 mg/kg (cat, oral)
128 mg/kg (mouse, oral)
230 mg/kg (rat, oral) [2]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 5 mg/m3 [1]
REL (Recommended)
TWA 5 mg/m3 [1]
IDLH (Immediate danger)
100 mg/m3 [1]
Safety data sheet (SDS) ICSC 0121
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Spraying carbaryl on pine trees Copy of DSC 0269 (6882742253).jpg
Spraying carbaryl on pine trees

Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid previously sold under the brand name Sevin, which was a trademark of the Bayer Company. The Sevin trademark has since been acquired by GardenTech, which has eliminated carbaryl from most Sevin formulations. [3] [4] Union Carbide discovered carbaryl and introduced it commercially in 1958. Bayer purchased Aventis CropScience in 2002, a company that included Union Carbide pesticide operations. Carbaryl was the third-most-used insecticide in the United States for home gardens, commercial agriculture, and forestry and rangeland protection. As a veterinary drug, it is known as carbaril (INN).

Contents

Production

Carbaryl is often inexpensively produced by direct reaction of methyl isocyanate with 1-naphthol. [5]

C10H7OH + CH3NCO → C10H7OC(O)NHCH3

Alternatively, 1-naphthol can be treated with excess phosgene to produce 1-naphthyl chloroformate, which is then converted to carbaryl by reaction with methylamine. [5] The former process was carried out in Bhopal. In comparison, the latter synthesis uses exactly the same reagents, but in a different sequence. This procedure avoids the potential hazards of methyl isocyanate.

Biochemistry

Carbamate insecticides are slowly reversible inhibitors of the enzyme acetylcholinesterase. They resemble acetylcholine, but the carbamoylated enzyme undergoes the final hydrolysis step very slowly (minutes) compared with the acetylated enzyme generated by acetylcholine (microseconds). They interfere with the cholinergic nervous system and cause death because the effects of the neurotransmitter acetylcholine cannot be terminated by carbamoylated acetylcholinesterase.

Applications

The development of the carbamate insecticides has been called a major breakthrough in pesticides. The carbamates do not have the persistence of chlorinated pesticides. Although toxic to insects, carbaryl is detoxified and eliminated rapidly in vertebrates. It is neither concentrated in fat nor secreted in milk, so is favored for food crops, at least in the US. [6] It is the active ingredient in Carylderm shampoo used to combat head lice until infestation is eliminated. [7]

Ecology

Carbaryl kills both targeted (e.g., malaria-carrying mosquitos) and beneficial insects (e.g., honeybees), as well as crustaceans. [8] Because it is highly toxic to zooplankton, the algae they feed on experience blooms. Boone & Bridges 2003 find that larger algae eaters such as Bufo woodhousii benefit from this effect. [9]

Although it can increase survival rates for organisms that benefit from consequential algae blooms, the long term effects of these changes in competition levels and predation can be detrimental to many aquatic ecosystems, particularly those dominated by Anurans. [10]

It is approved for more than 100 crops in the US. Carbaryl is illegal in the EU [11] and Angola. [12]

Safety

Carbaryl is a cholinesterase inhibitor and is toxic to humans. It is classified as a likely human carcinogen by the United States Environmental Protection Agency (EPA.) [13] The oral LD50 is 250 to 850 mg/kg for rats and 100 to 650 mg/kg for mice. [8]

Carbaryl can be produced using methyl isocyanate (MIC) as an intermediary. [5] A leak of MIC used in the production of carbaryl caused the Bhopal disaster, the most lethal industrial accident in history. [14]

Related Research Articles

<span class="mw-page-title-main">Pesticide</span> Substance used to destroy pests

Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampricide. The most common of these are herbicides, which account for approximately 50% of all pesticide use globally. Most pesticides are intended to serve as plant protection products, which in general, protect plants from weeds, fungi, or insects. In general, a pesticide is a chemical or biological agent that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, cause nuisance, or spread disease, or are disease vectors. Along with these benefits, pesticides also have drawbacks, such as potential toxicity to humans and other species.

<span class="mw-page-title-main">Methyl isocyanate</span> Chemical compound

Methyl isocyanate (MIC) is an organic compound with the molecular formula CH3NCO. Synonyms are isocyanatomethane and methyl carbylamine. Methyl isocyanate is an intermediate chemical in the production of carbamate pesticides (such as carbaryl, carbofuran, methomyl, and aldicarb). It has also been used in the production of rubbers and adhesives. As an extremely toxic and irritating compound, it is very hazardous to human health. It was the principal toxicant involved in the infamous Bhopal gas disaster, which officially killed around 20,000 people in total. It is also a very potent lachrymatory agent.

<span class="mw-page-title-main">Carbamate</span> Chemical group (>N–C(=O)–O–)

In organic chemistry, a carbamate is a category of organic compounds with the general formula R2NC(O)OR and structure >N−C(=O)−O−, which are formally derived from carbamic acid. The term includes organic compounds, formally obtained by replacing one or more of the hydrogen atoms by other organic functional groups; as well as salts with the carbamate anion H2NCOO−.

<span class="mw-page-title-main">Parathion</span> Chemical compound

Parathion, also called parathion-ethyl or diethyl parathion and locally known as "Folidol", is an organophosphate insecticide and acaricide. It was originally developed by IG Farben in the 1940s. It is highly toxic to non-target organisms, including humans, so its use has been banned or restricted in most countries. The basic structure is shared by parathion methyl.

<span class="mw-page-title-main">Malathion</span> Chemical compound

Malathion is an organophosphate insecticide which acts as an acetylcholinesterase inhibitor. In the USSR, it was known as carbophos, in New Zealand and Australia as maldison and in South Africa as mercaptothion.

<span class="mw-page-title-main">Chlorfenvinphos</span> Chemical compound

Chlorfenvinphos is an organophosphorus compound that was widely used as an insecticide and an acaricide. The molecule itself can be described as an enol ester derived from dichloroacetophenone and diethylphosphonic acid. Chlorfenvinphos has been included in many products since its first use in 1963. However, because of its toxic effect as a cholinesterase inhibitor it has been banned in several countries, including the United States and the European Union. Its use in the United States was cancelled in 1991.

<span class="mw-page-title-main">Diazinon</span> Chemical compound

Diazinon, a colorless to dark brown liquid, is a thiophosphoric acid ester developed in 1952 by Ciba-Geigy, a Swiss chemical company. It is a nonsystemic organophosphate insecticide formerly used to control cockroaches, silverfish, ants, and fleas in residential, non-food buildings. Diazinon was heavily used during the 1970s and early 1980s for general-purpose gardening use and indoor pest control. A bait form was used to control scavenger wasps in the western U.S. Diazinon is used in flea collars for domestic pets in Australia and New Zealand. Residential uses of diazinon were outlawed in the U.S. in 2004 because of human health risks but it is still approved for agricultural uses. An emergency antidote is atropine.

Demeton-S-methyl is an organic compound with the molecular formula C6H15O3PS2. It was used as an organothiophosphate acaricide and organothiophosphate insecticide. It is flammable. With prolonged storage, Demeton-S-methyl becomes more toxic due to formation of a sulfonium derivative which has greater affinity to the human form of the acetylcholinesterase enzyme, and this may present a hazard in agricultural use.

<span class="mw-page-title-main">Aldicarb</span> Chemical compound (insecticide)

Aldicarb is a carbamate insecticide which is the active substance in the pesticide Temik. It is effective against thrips, aphids, spider mites, lygus, fleahoppers, and leafminers, but is primarily used as a nematicide. Aldicarb is a cholinesterase inhibitor which prevents the breakdown of acetylcholine in the synapse. Aldicarb is considered "extremely hazardous" by the EPA and World Health Organization and has been banned in more than 100 countries. In case of severe poisoning, the victim dies of respiratory failure.

<span class="mw-page-title-main">Azinphos-methyl</span> Chemical compound

Azinphos-methyl (Guthion) is a broad spectrum organophosphate insecticide manufactured by Bayer CropScience, Gowan Co., and Makhteshim Agan. Like other pesticides in this class, it owes its insecticidal properties to the fact that it is an acetylcholinesterase inhibitor. It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act, and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.

<span class="mw-page-title-main">Phosmet</span> Organophosphate non-systemic insecticide

Phosmet is a phthalimide-derived, non-systemic, organophosphate insecticide used on plants and animals. It is mainly used on apple trees for control of codling moth, though it is also used on a wide range of fruit crops, ornamentals, and vines for the control of aphids, suckers, mites, and fruit flies.

<span class="mw-page-title-main">Dioxathion</span> Chemical compound

Dioxathion, systematically known as p-dioxane-2,3-diyl ethyl phosphorodithioate, is an organophosphate pesticide. It is used as an insecticide on livestock and as an acaricide on citrus fruits, deciduous fruits and nuts.

<span class="mw-page-title-main">Bendiocarb</span> Insecticide

Bendiocarb is an acutely toxic carbamate insecticide used in public health and agriculture and is effective against a wide range of nuisance and disease vector insects. Many bendiocarb products are or were sold under the tradenames "Ficam" and "Turcam."

<span class="mw-page-title-main">Methomyl</span> Chemical compound

Methomyl is a carbamate insecticide introduced in 1966. It is highly toxic to humans, livestock, pets, and wildlife. The EU and UK imposed a pesticide residue limit of 20 µg/kg for apples and oranges.

<span class="mw-page-title-main">Methiocarb</span> Chemical compound

Methiocarb is a carbamate pesticide which is used as an insecticide, bird repellent, acaricide and molluscicide since the 1960s. Methiocarb has contact and stomach action on mites and neurotoxic effects on molluscs. Seeds treated with methiocarb also affect birds. Other names for methiocarb are mesurol and mercaptodimethur.

<span class="mw-page-title-main">Disulfoton</span> Chemical compound

Disulfoton is an organophosphate acetylcholinesterase inhibitor used as an insecticide. It is manufactured under the name Di-Syston by Bayer CropScience. Disulfoton in its pure form is a colorless oil but the technical product used in vegetable fields is dark and yellowish with a sulfur odor. Disulfoton is processed as a liquid into carrier granules, these granules are mixed with fertilizer and clay to be made into a spike, designed to be driven into the ground. The pesticide is absorbed over time by the roots and translocated to all parts of the plant. The pesticide acts as a cholinesterase inhibitor and gives long lasting control.

<span class="mw-page-title-main">Propoxur</span> Chemical compound

Propoxur (Baygon) is a carbamate non-systemic insecticide, produced from catechol, and was introduced in 1959. It has a fast knockdown and long residual effect, and is used against turf, forestry, and household pests and fleas. It is also used in pest control for domestic animals, Anopheles mosquitoes, ants, gypsy moths, and other agricultural pests. It can also be used as a molluscicide.

<span class="mw-page-title-main">Acetylcholinesterase inhibitor</span> Drugs that inhibit acetylcholinesterase

Acetylcholinesterase inhibitors (AChEIs) also often called cholinesterase inhibitors, inhibit the enzyme acetylcholinesterase from breaking down the neurotransmitter acetylcholine into choline and acetate, thereby increasing both the level and duration of action of acetylcholine in the central nervous system, autonomic ganglia and neuromuscular junctions, which are rich in acetylcholine receptors. Acetylcholinesterase inhibitors are one of two types of cholinesterase inhibitors; the other being butyryl-cholinesterase inhibitors. Acetylcholinesterase is the primary member of the cholinesterase enzyme family.

<span class="mw-page-title-main">Tetraethyl pyrophosphate</span> Chemical compound

Tetraethyl pyrophosphate, abbreviated TEPP, is an organophosphate compound with the formula [(C2H5O)2P(O)]2O. It is the tetraethyl derivative of pyrophosphate (P2O74-). It is a colorless oil that solidifies near room temperature. It is used as an insecticide. The compound hydrolyzes rapidly.

<span class="mw-page-title-main">Sulfotep</span> Chemical compound

Sulfotep (also known as tetraethyldithiopyrophosphate and TEDP) is a pesticide commonly used in greenhouses as a fumigant. The substance is also known as Dithione, Dithiophos, and many other names. Sulfotep has the molecular formula C8H20O5P2S2 and belongs to the organophosphate class of chemicals. It has a cholinergic effect, involving depression of the cholinesterase activity of the peripheral and central nervous system of insects. The transduction of signals is disturbed at the synapses that make use of acetylcholine. Sulfotep is a mobile oil that is pale yellow-colored and smells like garlic. It is primarily used as an insecticide.

References

  1. 1 2 3 4 5 NIOSH Pocket Guide to Chemical Hazards. "#0100". National Institute for Occupational Safety and Health (NIOSH).
  2. ↑ "Carbaryl". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. ↑ "When Familiar Pesticides Change".
  4. ↑ "When is Sevin not Sevin?". 14 February 2018.
  5. 1 2 3 Thomas A. Unger (1996). Pesticide Synthesis Handbook (Google Books excerpt). William Andrew. pp. 67–68. ISBN   0-8155-1401-8.
  6. ↑ Robert L. Metcalf "Insect Control" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2002. doi : 10.1002/14356007.a14_263
  7. ↑ Carbaryl against lice
  8. 1 2 Carbaryl General Fact Sheet - National Pesticide Information Center
  9. ↑ Kendall, Ronald; Lacher, Thomas E.; Cobb, George P.; Cox, Stephen B., eds. (2010). Wildlife Toxicology: Emerging Contaminant and Biodiversity Issues. Boca Raton: CRC. ISBN   978-1-4398-1794-0. OCLC   646404494. 5.4.1 Taxon-Wide Impacts — Pesticides and Contaminants, and Their Roles in the Decline of Amphibian Populations. Moore, Robin D.; Claude Gascon. pp. 111-145.
  10. ↑ Boone, Michelle D.; Semlitsch, Raymond D. (February 2002). "Interactions of an Insecticide With Competition and Pond Drying in Amphibian Communities". Ecological Applications. 12 (1): 307–316. doi:10.1890/1051-0761(2002)012[0307:ioaiwc]2.0.co;2. ISSN   1051-0761.
  11. ↑ "L_2007133EN.01004001.XML".
  12. ↑ Carbaryl Insecticide Hazard Data Archived May 11, 2010, at the Wayback Machine
  13. ↑ Interim Reregistration Eligibility Decision for Carbaryl Archived July 25, 2008, at the Wayback Machine , U.S. EPA, June 2003.
  14. ↑ Eckerman, Ingrid (2005). The Bhopal Saga—Causes and Consequences of the World's Largest Industrial Disaster. India: Universities Press. doi:10.13140/2.1.3457.5364. ISBN   81-7371-515-7.
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