Permethrin
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| Permethrin | |
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| General | |
| Systematic name | IUPAC: 3-Phenoxybenzyl (1RS)-cis,trans-3-(2,2-dichlorovinyl) |
| SMILES | c3ccccc3Oc(c2)cccc2COC(=O) C1C(C1(C)C)C=C(Cl)Cl |
| Chemical formula | C21H20Cl2O3 |
| Appearance | Colourless crystals |
| Molar mass | 391.28 g/mol |
| Properties | |
| Density and phase | 1.19 g/cm³, solid |
| Solubility in water | Insoluble (5.5 x 10-3 ppm) |
| Melting point | 34 °C (307 K) |
| Boiling point | 200 °C (473 K) |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Irritating to skin and eyes, damaging to lungs |
| NFPA 704 |
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| Flash point | ?°C |
| R/S statement | R: R36 R37 R38 S: ? |
| RTECS number | ? |
| Related compounds | |
| Related pyrethroids | Bifenthrin Deltamethrin |
| Related compounds | ? |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Permethrin is a common synthetic chemical, widely used as an insecticide and acaricide and as an insect repellent. It belongs to the family of synthetic chemicals called pyrethroids and functions as a neurotoxin, affecting neuron membranes by slowing the access of important sodium ions.
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[edit] Uses
In agriculture, Permethrin is mainly used on cotton, wheat, maize, and alfalfa crops, and is also used to kill parasites on chickens and other poultry. Its use is controversial since, as a broad-spectrum chemical, it kills indiscriminately; as well as the intended pests, it can harm beneficial insects including honey bees and small mammals such as mice.
However, permethrin can be used in a targeted manner as well. This is the basis for a method of reducing populations of the deer tick Ixodes scapularis (I. dammini). Biodegradable cardboard tubes stuffed with permethrin-treated cotton, are sold under the brand name Damminix. Mice collect the cotton for lining their nests, and the pesticide on the cotton kills any immature ticks that are feeding on the mice.[1]
Permethrin is also used in healthcare, to eradicate parasites such as head lice and scabies, and in industrial and domestic settings to control pests such as ants and termites.
Permethrin kills ticks on contact with treated clothing. According to the Connecticut Department of Public Health, it "has low mammalian toxicity, is poorly absorbed through the skin and is rapidly inactivated by the body. Skin reactions have been uncommon." [2]
Permethrin is used in tropical areas to prevent mosquito-borne disease such as Dengue fever and malaria. Mosquito nets used to cover beds may be treated with a solution of permethrin. Military personnel training in malaria-endemic areas may be instructed to treat their uniforms with permethrin as well. An application should last several washes.
[edit] Products containing permethrin
Products containing 0.5% permethrin:
- Repel Permanone
- Permethrin Tick Repellent
[edit] Stereochemistry
Permethrin has four stereoisomers (two enantiomeric pairs), arising from the two stereocentres in the cyclopropane ring. The trans enantiomeric pair is known as transpermethrin.
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[edit] Aquatic Toxicity
Permethrin is extremely toxic to fish. Extreme care must be taken when using products containing permethrin near water courses.
[edit] References
- ^ Protecting Property from Tick Infestation: Damminix [1] University of Maryland Medical Center
- ^ Tick bite prevention - Connecticut Department of Public Health
