Profenofos

Description

Profenofos is a pale yellow liquid, bp 100 ?C/1.80 Pa, vp 0.124 mPa (25 ?C). Solubility in water is 28 mg/L (25 ?C). It is miscible with most organic solvents. Log Kow = 4.44. It is relatively stable in neutral and mild acid media but hydrolyzed in alkaline media; DT₅₀ values (20 ?C) at pH 5, 7, and 9 are 93 d, 14.6 d, and 5.7 h, respectively.

Chemical Properties

Profenofos is a pale yellow liquid. Profenofos is relatively stable under neutral and slightly acidic conditions and unstable under alkaline conditions.Profenofos has a garlic-like odor.
Profenofos has limited solubility in water (28 mg/L at 25°C) but is completely soluble in organic solvents (ethanol, acetone, toluene, n-octanol and n-hexane) at 25°C.

Uses

A broad-spectrum organophosphorous pesticide that is used widely in cotton fields for insect control.

Uses

Insecticide; acaricide.

Uses

Profenofos is used to control insects (particularly caterpillars and Lepidoptera eggs) and mites on cotton, maize, sugar beet, soyabean, potatoes, vegetables, tobacco and a number of other crops

Definition

ChEBI: Profenofos is an organic thiophosphate, an organophosphate insecticide, an organochlorine insecticide and a member of monochlorobenzenes. It has a role as an EC 3.1.1.7 (acetylcholinesterase) inhibitor, an acaricide and an agrochemical. It is functionally related to a 4-bromo-2-chlorophenol.

General Description

Pale yellow liquid with garlic-like odor. Corrosive. Used as an insecticide.

Air & Water Reactions

Hydrolyzed under alkaline conditions.

Reactivity Profile

Organophosphates are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides.

Agricultural Uses

Profenofos: Profenofos is A U.S. EPA restricted Use Pesticide (RUP) used solely on cotton to control a number of pests including tobacco budworm, cotton aphid and bollworm, armyworm, fleahopper and whiteflies. It is not registered for residential use. Not approved for use in EU countries. Registered for use in the U.S.

Trade name

CGA-15324®; CURACRON®; POLYCRON®; SELECRON®

Carcinogenicity

In a 2 year carcinogenicity study mice were given diets containing 0, 1, 30, or 100 ppm profenofos (equivalent to 0, 0.15, 4.5, or 15 mg/kg/day) for 85 weeks (males) or 97 weeks (females) . No treatment related clinical signs were observed. No treatment-related gross or microscopic lesions, tumors, or biologically significant differences in body weight or food consumption were observed between controls and profenofos-treated animals. Plasma and erythrocyte cholinesterase inhibition occurred at dose levels of 4.5 and 15 mg/kg/day. In another carcinogenicity study, rats were fed diets containing 0, 0.3, 10, or 100 ppm profenofos (equivalent to 0, 0.015, 0.5, or 5 mg/kg/day) for 2 years, and there was no increase in tumor incidence in any treated group compared to the control group .

Environmental Fate

Plant. Dislodgable residues of profenofos on cotton leaf 0, 24, 48, 72 and 96 hours after application (1.1 kg/ha) were 3.5, 1.1, 0.74, 0.51 and 0.35 μg/m2, respectively (Buck et al., 1980)
Photolytic. When profenofos in an aqueous buffer solution (pH 7.0) was exposed to filtered UV light (λ >290 nm) for 24 hours at 25 and 50°C, 29 and 61% respectively decomposed to 4-bromo-2-chlorophenol and 4-bromo-2-chlorophenyl ethyl hydrogen ph
Chemical/Physical. Emits toxic fumes of bromine, chlorine phosphorus and sulfur oxides when heated to decomposition (Sax and Lewis, 1987).

Metabolic pathway

The metabolic transformations of profenofos in plants and animals are similar and occur via hydrolysis to 4-bromo-2-chlorophenol which is then conjugated.

Metabolism

Profenofos orally administered to rats is rapidly excreted, mainly in the urine. The principal degradation route is hydrolysis to 4-bromo-2-chlorophenol followed by conjugation. DT₅₀ in soil is about 1 week.

Toxicity evaluation

The acute oral LD₅₀ for rats is 358 mg/kg. Inhalation LC50 (4 h) for rats is about 3 mg/L air. NOEL (2 yr) for rats is 0.3 mg/kg diet (0.015 mg/kg/d). ADI is 0.01 mg/kg b.w.

Degradation

Profenofos is stable under neutral and slightly acid conditions but it is hydrolysed in alkaline solution. The DT₅₀ values at pH 5, 7 and 9 (20°C) were 93 days, 14.6 days and 5.7 hours, respectively (PM).