Common name:    Methyl Parathion 

Other name: Trade names include Bladan M, Cekumethion, Dalf, Dimethyl Parathion.

Iupac name: O,O-dimethyl O-4-nitrophenyl phosphorothioate

Type: Insecticide for Agriculture

CAS RN:  298-00-0

M.F.: C₈H₁₀NO₅PS

Mol Wt: 263.21                  

 

Form (appearance): Pure methyl parathion is a colorless crystalline solid. The technical product is light to dark tan, with about 80% purity

Composition: Tech. grade is c. 80%.
M.P.: 35-36 C

B.P.: 143 C

V.P.: 1.3 mPa @ 20 C

F.P.: 46 ℃ (tech., Pensky-Martens closed cup)

S.G.:1.36 g/mi (25℃)

Solubility.: 55-60 mg/L @ 25 C. in dichloromethane, 2-propanol, toluene, and most organic solvents; i.s. in n-hexane.

Stability: Stable to light. Stable on storage for more than 6 months at 15-25 ℃.

Henry: 2 × 10^-2 Pa m³ mol^-1

K_owlogP: 7 (20℃)

Pka: >9 (hydrolysis prevents measurement)

 

Formulation types: EC

Mode of action: Non-systemic insecticide with contact and stomach action, and repellent properties. Gives rapid knockdown and long residual activity

Uses: Methyl parathion is an organophosphate insecticide and acaricide used to control boll weevils and many biting or sucking insect pests of agricultural crops, primarily on cotton. It kills insects by contact, stomach and respiratory action. Methyl parathion is available in dust, emulsifiable concentrate, ULV liquid, and wettable powder formulations.

 

Oral: Acute oral LD₅₀ for male rats 50, female rats 14.5, mice 19.5 mg/kg.

Skin and eye: Acute percutaneous LD₅₀ for rats 632-696 mg/kg. Mild eye irritant; non-irritant to skin (rabbits). Not a skin sensitiser (guinea pigs).

Inhalation: LC₅₀ (4 h) 0.6 mg/l air (total particulate).

Noel: (1 y) for dogs 0.05 mg/kg daily.

ADI: 0.005 mg/kg.
Other Non-mutagenic in the Ames test.

Toxicity: WHO (a.i.) II; EPA (formulation) II (`Karate`, `Warrior`)

EC hazard: T+; R26| T; R25| Xn; R21| N; R50, R53

 

Birds: Methyl parathion is very highly to highly toxic to birds. Reported acute oral LD50 values are 3 mg/kg in American kestrels, 7.5 mg/kg in European starlings, 6 to 10 mg/kg in mallards, 8 mg/kg in northern bobwhites, 10 to 24 mg/kg in red-wing blackbirds,and 8 mg/kg in ring-neck pheasants. The 5- to 8-day dietary LC50 values reported for methyl parathion include 69 ppm in Japanese quail, 330 to 680 ppm in mallard, 90 ppm in northern bobwhite, and 91 ppm in ring-neck pheasant.

Fish: Methyl parathion is moderately toxic to fish and to animals that eat fish. Reported 96-hour LC50 values are from 1.9 to 8.9 mg/L in the following fish species: coho salmon, cutthroat trout, rainbow trout, brown trout, lake trout, goldfish, carp, fathead minnow, black bullhead, channel catfish, green sunfish, bluegill, largemouth bass, and yellow perch. Reported 96-hour LC50 values indicate very high toxicity for aquatic invertebrates such as Daphnia spp., scuds, and sideswimmers.

PACKAGE: 250KG DRUM.