carbaryl

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (July 2007)

Carbaryl
IUPAC name	1-naphthyl methylcarbamate
Other names	Sevin
Identifiers
CAS number	63-25-2 Y
EC number	200-555-0
UN number	2757
RTECS number	FC5950000
SMILES	O=C(Oc2cccc1ccccc12)NC
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)
InChI key	CVXBEEMKQHEXEN-UHFFFAOYAZ
ChemSpider ID	5899
Properties
Molecular formula	C12H11NO2
Molar mass	201.22 g/mol
Appearance	Colorless crystalline solid
Density	1.2 g/cm3
Melting point	142 °C
Boiling point	decomposes before boiling
Solubility in water	very low
Hazards
MSDS	ICSC 0121
EU Index	006-011-00-7
EU classification	Carc. Cat. 3 Harmful (Xn) Dangerous for the environment (N)
R-phrases	R20/22, R40, R50
S-phrases	(S2), S22, S24, S36/37, S46, S61
Flash point	193–202 °C
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate family used chiefly as an insecticide. It is a colorless white crystalline solid commonly sold under the brand name Sevin, a trademark of the Bayer Company. Union Carbide discovered carbaryl and introduced it commercially in 1958. Bayer purchased Aventis CropScience in 2002, a company that included Union Carbide pesticide operations. It remains the third-most-utilized insecticide in the United States for home gardens, commercial agriculture, and forestry and rangeland protection.

Production

As in the Bhopal disaster,^{[citation needed]} carbaryl can be produced by reacting methylamine (1) with phosgene (2), undergoing elimination to give methyl isocyanate (3). Methyl isocyanate reacts with 1-naphthol (4) to give carbaryl (5):^[1]

An alternate synthesis which bypasses the toxic methyl isocyanate reagent exists: 1-naphthol (1) is reacted with phosgene (2) to give the chloroformate (3), which reacts further with methylamine to give the desired product (4):^[1]

Biochemistry

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.)^[2] It kills various beneficial insect and crustacean species along with intended pest victims, so care must be taken when spraying where beneficial nontarget species are present. Carbaryl is acutely toxic to honeybees, destroying colonies of bees foraging in an area where the chemical has been applied.

Oral LD₅₀:

• 250 mg/kg to 850 mg/kg for rats
• 100 mg/kg to 650 mg/kg for mice

When ingested by people it is metabolized rapidly and excreted in the urine.

Active Ingredient in Carylderm (R) shampoo used to combat head lice
In Austria, the pharmacy will sell, without a prescription, this shampoo containing 1 gram Carbaryl per 100 gram shampoo. Treatment for head lice involves shampooing on days 1, 3, and 7 until infestation is eliminated.

Carbaryl is illegal in several countries, including the United Kingdom, Austria, Denmark, Sweden, Germany and Angola.^[3]

References

1. ^ ^{a b} Thomas A. Unger (1996) (Google Books excerpt). Pesticide synthesis handbook. William Andrew. pp. 67-68. ISBN 0815514018. http://books.google.com/books?id=blYN-_pY9_IC&pg=PA67. 
2. ^ Interim Reregistration Eligibility Decision for Carbaryl, U.S. EPA, June 2003.
3. ^ Carbaryl Insecticide Hazard Data

External links

• Carbaryl Technical Fact Sheet - National Pesticide Information Center
• Carbaryl General Fact Sheet - National Pesticide Information Center
• Carbaryl Pesticide Information Profile - Extension Toxicology Network
• Cholinesterase Inhibition - Extension Toxicology Network
• EPA info
• EPA factsheet
• IPCS (WHO) Health and Safety Guide
• Environmental Health Criteria - WHO
• Exclusive Chemistry Ltd - routes of Sevin synthesis