Chemistry:Metam sodium

From HandWiki
Metam sodium[1]
Metham sodium.png
Ball-and-stick model of the component ions of metham sodium
Names
Preferred IUPAC name
Sodium methylcarbamodithioate
Other names
Metham sodium
Carbathion
Carbathione
Carbothion
Metamsodium
Metam-sodium
Identifiers
3D model (JSmol)
ChemSpider
UNII
Properties
C2H4NNaS2
Molar mass 129.18 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☑Y verify (what is ☑Y☒N ?)
Infobox references
Tracking categories (test):

Metam sodium is an organosulfur compound with the formula CH
3
NHCS
2
Na
. The compound is a sodium salt of a dithiocarbamate. The compound exists as a colorless dihydrate, but most commonly it is encountered as an aqueous solution.[2] It is used as a soil fumigant, pesticide, herbicide, and fungicide. It is one of the most widely used pesticides in the United States, with approximately 60 million pounds used in 2001.[3]

Preparation and properties

Metam sodium is prepared by combining methylamine, carbon disulfide, and sodium hydroxide:[2]

CH
3
NH
2
+ CS
2
+ NaOH → CH
3
NHCS
2
Na + H
2
O

It also arises from the reaction of methyl isothiocyanate and sodium thiolate.[1]

Upon exposure to the environment, metam sodium decomposes to methyl isothiocyanate.[4]

Safety and environmental considerations

Metam sodium is nonpersistent in the environment since it is prone to hydrolysis. The degradation products, carbon disulfide and methyl amine are however toxic. In 1991 a tank car with 19,000 gallons of metam sodium spilled into Sacramento River above Lake Shasta. This killed all fish in a 41-mile stretch of the river. By 20 years later the rainbow trout population had recovered.[5]

See also

References

  1. 1.0 1.1 Merck Index, 11th Edition, 5860.
  2. 2.0 2.1 Hartwig, Jürgen; Sommer, Herbert; Müller, Franz (2008). "Nematicides". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a17_125.pub2. ISBN 978-3527306732. 
  3. 2000-2001 Pesticide Market Estimates , U.S. Environmental Protection Agency
  4. Review of Metam Sodium, Dazomet, Methylisothiocyanate (MITC) , Australian Pesticides and Veterinary Medicines Authority, June 1997
  5. "Largest chemical spill in California history" (in en). https://dtsc.ca.gov/20th-anniversary-of-largest-chemical-spill-in-california-history/. 

External links