Title: Methanearsonic Acid
CAS Registry Number: 124-58-3
CAS Name: Methylarsonic acid
Additional Names: methylarsinic acid; monomethylarsinic acid
Molecular Formula: CH5AsO3
Molecular Weight: 139.97
Percent Composition: C 8.58%, H 3.60%, As 53.53%, O 34.29%
Line Formula: CH3AsO(OH)2
Literature References: Prepd from sodium arsenite and methyl iodide: Quick, Adams, J. Am. Chem. Soc. 44, 809 (1922). The disodium salt is easily prepd by treating sodium arsenite with dimethyl sulfate at 85°: Uhlinger, Cook, Ind. Eng. Chem. 11, 105 (1919). Other routes are by the reaction of methyl chloride with sodium arsonate under pressure: Miller et al., US 2442372 (1948); by the reaction of dimethyl sulfate with a solution of arsenic trioxide in sodium hydroxide: Schwerdle, US 2889347 (1959). Acute toxicity: T. B. Gaines, R. E. Linder, Fundam. Appl. Toxicol. 7, 299 (1986). Review of toxicology and human exposure: Toxicological Profile for Arsenic (PB2000-108021, 2000) 468 pp.
Properties: Monoclinic, spear-shaped plates from abs alcohol. Pleasant acid taste. mp 161°. Strong dibasic acid. Freely sol in water; sol in alcohol.
Melting point: mp 161°
Derivative Type: Monosodium salt
Additional Names: Monosodium methanearsonate; MSMA
Trademarks: Ansar 6.6 (ISK Biosci); Bueno (ISK Biosci); Daconate (ISK Biosci); Weed Hoe (Vineland)
Molecular Formula: CH4AsNaO3
Molecular Weight: 161.95
Percent Composition: C 7.42%, H 2.49%, As 46.26%, Na 14.20%, O 29.64%
Properties: LD50 in adult male, female rats (mg/kg): 1105, 1059 orally (Gaines, Linder).
Toxicity data: LD50 in adult male, female rats (mg/kg): 1105, 1059 orally (Gaines, Linder)
Derivative Type: Disodium salt
Additional Names: Disodium monomethanearsonate; DSMA
Trademarks: Ansar 8100 (ISK Biosci); Arrhenal (Cleary); Arsinyl (Cleary); Clout (Scott); Crab-E-Rad (Vineland); Dal-E-Rad (Vineland); Sodar
Molecular Formula: CH3AsNa2O3
Molecular Weight: 183.93
Percent Composition: C 6.53%, H 1.64%, As 40.73%, Na 25.00%, O 26.10%
Properties: Hydrated crystals contg 5H2O or 6H2O. One gram dissolves in about one ml water; slightly sol in alcohol. LD50 in adult male, female rats (mg/kg): 928, 821 orally (Gaines, Linder).
Toxicity data: LD50 in adult male, female rats (mg/kg): 928, 821 orally (Gaines, Linder)