Title: Malathion
CAS Registry Number: 121-75-5
CAS Name: [(Dimethoxyphosphinothioyl)thio]butanedioic acid diethyl ester
Additional Names: diethyl mercaptosuccinate S-ester with O,O-dimethyl phosphorothioate; S-(1,2-dicarbethoxyethyl) O,O-dimethyldithiophosphate; insecticide no. 4049; carbofos; malathon (obsolete); mercaptothion; phosphothion
Manufacturers' Codes: ENT-17034
Trademarks: Cythion; Derbac-M (International); Malamar 50; Malaspray; Organoderm (Mundipharma); Prioderm (Coates & Cooper); Suleo-M (International)
Molecular Formula: C10H19O6PS2
Molecular Weight: 330.36
Percent Composition: C 36.36%, H 5.80%, O 29.06%, P 9.38%, S 19.41%
Literature References: Cholinesterase inhibitor. Prepn: Johnson et al., J. Econ. Entomol. 45, 279 (1952); Cassaday, US 2578652 (1951 to Am. Cyanamid). Purification: Usui, US 2962521 (1960 to Sumitomo). Treatment of Pediculus humanus (head lice) infestation: D. Taplin et al., J. Am. Med. Assoc. 247, 3103 (1982). Toxicity data: T. B. Gaines, Toxicol. Appl. Pharmacol. 14, 515 (1969). Review of distribution, transport and fate in the environment: M. S. Mulla et al., Residue Rev. 81, 1-159 (1981); of carcinogenic risk: IARC Monographs 30, 103-129 (1983); of toxicology and human exposure: Toxicological Profile for Malathion (PB2004-100003, 2003) 327 pp.
Properties: Deep brown to yellow liq, mp 2.9°. bp0.7 156-157°. Characteristic odor. d425 1.23. nD25 1.4985. Vapor pressure at 30°: 4 ´ 10-5 mm Hg. Slightly sol in water (145 ppm). Misc with many organic solvents including alcohols, esters, ketones, ethers, aromatic and alkylated aromatic hydrocarbons and vegetable oils. Limited soly in certain paraffin hydrocarbons. Petroleum ether is sol to about 35% in malathion. Hydrolyzed at pH >7.0 or <5.0. Stable in an aq soln buffered to pH 5.26. LD50 in female, male rats (mg/kg): 1000, 1375 orally (Gaines).
Melting point: mp 2.9°
Boiling point: bp0.7 156-157°
Index of refraction: nD25 1.4985
Density: d425 1.23
Toxicity data: LD50 in female, male rats (mg/kg): 1000, 1375 orally (Gaines)
CAUTION: Potential symptoms of overexposure are miosis, aching eyes, blurred vision and lacrimation; eye and skin irritation; salivation; anorexia, nausea, vomiting, abdominal cramps, diarrhea, giddiness, confusion and ataxia; rhinorrhea, headache; tightening of chest, wheezing and laryngeal spasms. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 188.
Use: Insecticide.
Therap-Cat: Pediculicide.
Therap-Cat-Vet: Ectoparasiticide.
Keywords: Ectoparasiticide. |