Methylarsonic acid
| Identifiers | |
|---|---|
| ECHA InfoCard | 100.004.278 |
CompTox Dashboard (EPA)
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| Properties | |
| CH5AsO3 | |
| Molar mass | 139.970 g·mol−1 |
| Appearance | white solid |
| Melting point | 160.5 °C (320.9 °F; 433.6 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Methanearsonic acid is an organoarsenic compound with the formula CH3AsO3H2. It is a colorless, water-soluble solid. Salts of this compound, e.g. disodium methyl arsonate, have been widely used in as a herbicides and fungicides in growing cotton and rice.[1]
Near physiological pH, methanearsonic acid converts to its conjugate bases called methanearsonates. These include CH3AsO3H- and CH3AsO32-. The biomethylation of arsenic compounds is thought to start with the formation of methanearsonates. Thus, trivalent arsenic compounds are methylated to give methanearsonate. S-adenosylmethionine is the methyl donor. The methanearsonates are the precursors to dimethylarsonates, again by the cycle of reduction (to methylarsonous acid) followed by a second methylation.[2]
Safety
Like all arsenic compounds it is highly toxic.[2].
References
- ^ Grund, S. C.; Hanusch, K.; Wolf, H. U. "Arsenic and Arsenic Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_113.pub2. ISBN 978-3527306732.
{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link) - ^ a b "Archives of Toxicology". 74. 2000: 289–299. doi:10.1007/s002040000134.
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