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DEET

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DEET
DEET2
Systematic name N,N-diethyl-3-methylbenzamide
N,N-diethyl-m-toluamide
Chemical formula C12H17NO
Molecular mass 191.27 g/mol
Density 0.998 g/cm³
Melting point -45 °C
Boiling point 288-292 °C
CAS number [134-62-3]
SMILES CCN(CC)C(=O)C1=CC(=CC=C1)C
Disclaimer and references

Meta-N,N-diethyl toluamide, abbreviated DEET, is an insect-repellent chemical. It is intended to be applied to the skin or to clothing, and is primarily used to protect against insect bites. In particular, DEET protects against tick bites (which transmit Lyme disease) and mosquito bites (which transmit dengue fever, West Nile virus, Eastern Equine Encephalitis (EEE), and malaria).

DEET is believed to work by blocking insect receptors (notably those which detect carbon dioxide and lactic acid) which are used to locate hosts. DEET effectively "blinds" the insect's senses so the biting/feeding instinct is not triggered by humans or animals which produce these chemicals.

History

DEET was developed by the United States Army, following its experience of jungle warfare during World War II. It has been stated by some that malaria has caused more deaths in the pacific campaign than the war-action.[citation needed] It entered military use in 1946 and civilian use in 1957.

Chemistry

A slightly yellow liquid at room temperature, it can be prepared from m-methylbenzoic acid and diethylamine. This can be achieved by preparing the acid chloride and subsequently reacting that with the diethylamine. It can be distilled under vacuum: b.p. 111 oC at 1 mm Hg. It is considered a mild irritant.

Concentrations

DEET is available in many insect repellents

DEET is often sold and used in concentrations up to 100%. Consumer Reports found a direct correlation between DEET concentration and hours of protection against insect bites. 100% DEET was found to offer up to 12 hours of protection while several lower concentration DEET formulations (20%-34%) offered 3-6 hours of protection[1]. Other research has corroborated the effectiveness of DEET.[2]

Effects on health

DEET is the most common active ingredient in insect repellents. Studies into the health effects of using DEET in the approved way (as a topical application) have not shown any significant harm to human health; exposure to large amounts (by means such as accidental ingestion) has similar effects to comparable exposure to other pesticides. [citation needed] As DEET is a powerful pesticide, however, manufacturers of DEET based products advise they should not be used under clothing, on damaged skin, and that the DEET based preparation be washed off after it is no longer needed or between applications.[3] In rare cases, it may cause skin reactions.[3]

Recent studies by Duke University researchers have found that "laboratory rats treated with an average human dose of DEET (40 mg/kg body weight) performed far worse when challenged with physical tasks requiring muscle control, strength and coordination. These findings are consistent with reported human symptoms following DEET's use by the military in the Persian Gulf War." [4] Duke Pharmacologist Mohamed Abou-Donia, PhD, has said that the results of this study warrant further testing and he has warned the public to use insecticides containing DEET sparingly and infrequently -- he does note that "little information" exists about occasional use of DEET.[4]

The American Academy of Pediatrics found no difference in safety for children, between products containing 10% and 30% DEET, when used as directed, but recommends that DEET not be used on infants less than two months old.[3]

Effects on materials

DEET is an effective solvent which can damage some plastics, rayon, spandex, other synthetic fabrics, leather, and painted or varnished surfaces; it does not damage natural fibers, such as cotton or wool, and has no effect on nylon.

Effects on the environment

Although few studies have been conducted to assess possible effects on the environment, DEET is a powerful chemical pesticide and may not be suitable for use in and around water sources. Though DEET is not expected to bioaccumulate, it has been found to have a slight toxicity for coldwater fish such as the rainbow trout[5] and the tilapia [6], and it has also been shown to be toxic for some species of freshwater zooplankton [7]. DEET has been detected in significant levels in waterbodies as a result of production and use, such as in the Mississippi River and its tributaries, where a 1991 study detected levels varying from 5 to 201 ng/L [8]

Natural alternatives

Some repellents offer alternatives to DEET. Repellents containing picaridin or lemon eucalyptus oil were reported by Consumer Reports to be about as effective as repellents containing DEET,[9] though medical studies have differed on the effectiveness of alternatives. [10]

Another alternative is Citronella oil, which has been shown to be effective by some studies,[11] and ineffective by others. [12]

Catnip is marketed as a product against mosquito bites, but this product may not significantly reduce mosquito bites. [13]

While not marketed as a topical insect repellent, cinnamon oil has been shown to be more effective than DEET at killing mosquito larvae, with no adverse side effects on health or the environment. [14]

References

Notes

  1. ^ Essential oil analysis and field evaluation of the citrosa plant "Pelargonium citrosum" as a repellent against populations of Aedes mosquitoes. Matsuda, Brent M.; Surgeoner, Gordon A.; Heal, James D.; Tucker, Arthur O.; Maciarello, Michael J. Department of Environmental Biology, University of Guelph, Guelph, ON, Can. Journal of the American Mosquito Control Association (1996), 12(1), 69-74. Publisher: American Mosquito Control Association, CODEN: JAMAET ISSN: 8756-971X. Journal written in English.
  2. ^ "Independent study: DEET products superior for fending off mosquito bites". Retrieved May 19. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
  3. ^ a b c http://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm
  4. ^ a b "Use Caution When Using DEET". Retrieved July 20. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
  5. ^ "U.S. Environmental Protection Agency. 1980. Office of Pesticides and Toxic Substances. N,N-diethyl-m-toluamide (Deet) Pesticide Registration Standard. December, 1980. 83 pp". Retrieved July 20. {{cite web}}: Check date values in: |accessdate= (help)
  6. ^ "Mathai, AT; Pillai, KS; Deshmukh, PB (1989) Acute toxicity of deet to a freshwater fish, Tilapia mossambica : Effect on tissue glutathione levels. Journal of Environmental Biology. Vol. 10, no. 2, pp. 87-91". Retrieved July 20. {{cite web}}: Check date values in: |accessdate= (help); line feed character in |title= at position 147 (help)
  7. ^ "Biodegradation of the Insecticide N,N-Diethyl-m-Toluamide by Fungi: Identification and Toxicity of Metabolites". Retrieved July 20. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
  8. ^ "Errol Zeiger, Raymond Tice, Brigette Brevard, (1999) N,N-Diethyl-m-toluamide (DEET) [134-62-3] - Review of Toxicological Literature" (PDF). Retrieved July 20. {{cite web}}: Check date values in: |accessdate= (help)
  9. ^ "Update: Another good mosquito repellent". Retrieved June 18. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
  10. ^ Assessment of the efficacy of quwenling as a mosquito repellent. Collins, D. A.; Brady, J. N.; Curtis, C. F. Dep. Biol., Imp. Coll. Sci. Technol. Med., London, UK. Phytotherapy Research (1993), 7(1), 17-20. CODEN: PHYREH ISSN: 0951-418X. Journal written in English.
  11. ^ "U.S. EPA Citronella Factsheet". Retrieved July 20. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
  12. ^ Essential oil analysis and field evaluation of the citrosa plant "Pelargonium citrosum" as a repellent against populations of Aedes mosquitoes. Matsuda, Brent M.; Surgeoner, Gordon A.; Heal, James D.; Tucker, Arthur O.; Maciarello, Michael J. Department of Environmental Biology, University of Guelph, Guelph, ON, Can. Journal of the American Mosquito Control Association (1996), 12(1), 69-74. Publisher: American Mosquito Control Association, CODEN: JAMAET ISSN: 8756-971X. Journal written in English.
  13. ^ Feeding deterrent effects of catnip oil components compared with two synthetic amides against Aedes aegypti. Chauhan, Kamlesh R.; Klun, Jerome A.; Debboun, Mustapha; Kramer, Matthew. BA, PSI, Chemicals Affecting Insect Behavior Laboratory, USDA-ARS, Beltsville, MD, USA. Journal of Medical Entomology (2005), 42(4), 643-646. Publisher: Entomological Society of America, CODEN: JMENA6 ISSN: 0022-2585. Journal written in English.
  14. ^ "Cinnamon Oil Kills Mosquitoes Better Than DEET". Retrieved July 20. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)

See also

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