Pirimiphos-methyl

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Chemical Identification | General Product Information | Physical & Safety Data

Chemical Identification

Common Name

Pirimiphos-methyl

中文通用名

甲基嘧啶磷

IUPAC

O-2-diethylamino-6-methylpyrimidin-4-yl O,O-dimethyl phosphorothioate

CAS

O-[2-(diethylamino)-6-methyl-4-pyrimidinyl] O,O-dimethyl phosphorothioate

CAS No.

29232-93-7

Molecular Formula

C₁₁H₂₀N₃O₃PS

Molecular Structure

General Product Information

Category

Insecticides > Organophosphorus insecticides

Activity

Insecticide

Premix

Lambda-cyhalothrin+Pirimiphos-methyl

Physical & Safety Data

Physical Properties

Molecular weight:305.3; Physical form:Straw-coloured liquid. Density:1.17 (20 °C); 1.157 (30 °C); Composition:Tech. material is 88% pure. Melting point:15-18 °C ( tech.); Flash point:>46 °C; Vapour pressure:2 mPa (20 °C); 6.9 mPa (30 °C); 22 mPa (40 °C); Henry constant:6 × 10-2 Pa m3 mol-1 ( calc.); Partition coefficient(n-octanol and water):logP = 4.2 (20 °C, unionised); pKa:4.30; Solubility:In water 11 ( pH 5), 10 ( pH 7), 9.7 ( pH 9) (all in mg/l, 20 °C). Miscible with most organic solvents, e.g. alcohols, ketones, halogenated hydrocarbons.; Stability:Hydrolysed by concentrated acids and alkalis; DT50 2-117 d ( pH range 4-9, most stable at pH 7). In sunlight, aqueous solution had DT50 <1 h.

Toxicology

Oral:Acute oral LD₅₀ for rats 1414, mice 1180 mg/ kg. Percutaneous:Acute percutaneous LD₅₀ for rats >2000 mg/kg. Slight eye and mild skin irritation (rabbits). Mild skin sensitiser (guinea pigs). Inhalation: LC₅₀ (4 h) for rats >5.04 mg/l. ADI:( JMPR) 0.02 mg/ kg b.w. [1982].

Environmental Profile

Ecotoxicology:
Algae: EC₅₀ 1.0 mg/l.Bees:Toxic to bees.Birds:Acute oral LD₅₀ for bobwhite quail 40, Japanese quail 140, mallard ducks 1695 mg/ kg.Daphnia: EC₅₀ (48 h) 0.21µg/l; (21 d) 0.08µg/l.Fish: LC₅₀ (96 h) for rainbow trout 0.64 mg/l; (48 h) for mirror carp 1.4 mg/l.Worms: LC₅₀ (14 d) 419 mg/ kg.

Environmental fate:
Animals:In mammals, the P-O bond is cleaved extensively and N-dealkylation and/or conjugation is a further step in the metabolism of the pyrimidine leaving group.Soil:Soil DT₅₀ (aerobic and anaerobic) is typically 3.5-25 d.Plant:Rapidly evaporates. After 2-3 days, <10% remains on plants, including the degradation product O-2-ethylamino-6-methylpyrimidin-4-yl O,O-dimethyl phosphorothioate. WATER SOLUBILITY: Approx. 5 ppm at 30°C

Transport Information

Signal Word:WARNING; Hazard Class:II(Moderately hazardous)