Fenuron

Herbicides

Active substance -> EU Pesticides database: Not approved

Pesticides -> Herbicides, Urea Derivative

Pesticide (Fenuron) -> USDA PDB

Pesticide

White, crystalline solid

Colorless crystalline solid

Colorless crystals

Sol in water 4.8 g/l at room temperature. Moderately sol in acetone and aromatic solvents. sparingly soluble in petroleum oils. /Fenuron trichloroacetate/

3850 ppm @ 25 °C

Sparingly sol in water (0.29% at 24 °C)

Solubility (25 °C): 3.85 g/l water; sparingly soluble in hydrocarbons.

In ethanol 108.8, diethylether 5.5, acetone 80.2, benzene 3.1, chloroform 125, n-hexane 0.2, groundnut oil 1.0 (all in g/kg at 20-25 °C)

In water 3.85 g/l at 25 °C

Fenuron decomposes in boiling strong bases or mineral acids.

When heated to decomp ... emits toxic fumes of /nitrogen oxides/.

133-134 °C

Melting point: 65-68 °C /Fenuron trichloroacetate/

0.0000375 [mmHg]

1.6x10-4 mm Hg at 60 °C

Dry Powder

White or colorless solid; [HSDB] Off-white powder; [MSDSonline]

This chemical does not meet GHS hazard criteria for 12.6% (25 of 199) of reports.

Warning

H319 (27.1%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

P203, P261, P264+P265, P271, P273, P280, P304+P340, P305+P351+P338, P318, P319, P337+P317, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 199 reports by companies from 9 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Chemical: Urea, N,N-dimethyl-N'-phenyl-

Urea, N,N-dimethyl-N'-phenyl- is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Urea, N,N-dimethyl-N'-phenyl- are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

REACH registered substance: Fenuron (EC: 202-941-4)

Urea, N,N-dimethyl-N'-phenyl-: Does not have an individual approval but may be used under an appropriate group standard

Urea-derived herbicides have low toxicity in animal feeding studies; May induce methemoglobinemia; After daily doses of 150 mg/kg for 10 months, guinea pigs had anemia, hypothyroidism, and injury to the liver, kidneys, and heart; No effects in rats fed 500 ppm for 90 days; [HSDB] Systemic toxicity unlikely unless large amounts ingested; [EPA Pesticides, p. 122] May be hydrolyzed to aniline causing methemoglobinemia; [Merck Index] May cause irritation; May induce methemoglobinemia; [MSDSonline]

TERRESTRIAL FATE: In soil, enzymic and microbial degradation involves step by step N-demethylation.

TERRESTRIAL FATE: The complete degradation of fenuron in soil has been experimentally determined to be 4.5 months at 15 °C and 2.2 months at 30 °C(1). Biodegradation will be the primary fate process in soil(2). Measured Kocs of 27(3) and 43(4) indicate that adsorption to soil will not be important(SRC). A visible change in color occurred within 2 hours when paper saturated with fenuron was exposed to sunlight(5) suggesting that some fenuron may be removed from soil surfaces via direct photolysis(SRC).

AQUATIC FATE: After 2 weeks, approximately 20% of 10 ug/L fenuron remained in raw river water samples exposed to sunlight and artificial fluorescent light(1). Biodegradation is expected to be the primary fate process in aquatic ecosystems(2,SRC). Measured Kocs of 27(3) and 43(4) indicate that adsorption of fenuron from the water column to sediment and suspended material will not be important(SRC). An estimated BCF of 6(3) indicates that fenuron will not bioconcentrate in fish(SRC). A visible change in color occurred within 2 hours when paper saturated with fenuron was exposed to sunlight(5) suggesting that some fenuron may be removed from water via direct photolysis(SRC). Volatilization from water will not be important(7) based on a low Henry's Law constant of 1.68X10-10 atm-cu m/mole at 25 °C(6,SRC).

ATMOSPHERIC FATE: Based on a measured water solubility of 4,027 mg/L at 25 °C(1) and an estimated Henry's Law constant of 9.71X10-10 atm-cu m/mole at 25 °C(2), the vapor pressure of fenuron can be estimated to be 1.81E-5 mm Hg at 25 °C(SRC). This vapor pressure value suggests that fenuron will exist in the vapor and particulate phases in the ambient atmosphere(3). Vapor-phase fenuron is rapidly degraded in the ambient atmosphere by reaction with photochemically formed hydroxyl radicals; the half-life for this reaction in air can be estimated to be about 2.3 hrs(4,SRC). A visible change in color occurred within 2 hours when paper saturated with fenuron was exposed to sunlight(5) suggesting that fenuron may be removed from the atmosphere via direct photolysis(SRC). Particulate-phase fenuron is removed via dry deposition(SRC).

Based on extensive biological and chemical studies, the disappearance of fenuron from soil is due primarily to microbial degradation; however, no quantitative data were given(1). In a pure culture study, fenuron was degraded 10% by the soil fungus Rhizoctonia solani after 6 days(2).

The Henry's Law constant for fenuron can be estimated to be 9.71X10-10 atm-cu m/mole at 25 °C based on a structure activity relationship(1). According to a suggested classification scheme(2), this value of Henry's Law constant indicates that fenuron will be essentially nonvolatile from water.

Rats given 500 ppm in food for 90 days showed no ill effects. However, in guinea pigs daily oral doses of 15 to 150 mg/kg for 10 months produced anemia, hypothyroidism and structural alterations in liver, kidney, spleen and myocardium. Cows and sheep receiving 2 to 5 daily doses of 500 mg/kg showed anorexia and incoordination progressing to death. In surviving animals, recovery was extremely slow. Necropsy revealed congestion of lungs and myocardial hemorrhages. Practically nonirritating to intact skin of guinea pigs and only moderately irritating to abraded skin. Not a skin sensitizer.

Substituted urea compounds (... fenuron) cause vomiting, ataxia, and urticaria.

In 90 day feeding trials, rats receiving 500 mg/kg diet showed no ill effects.

Fenuron ... /is/ degraded by light

The rate constant for the vapor-phase reaction of fenuron with photochemically produced hydroxyl radicals can be estimated to be 1.68X10-10 cu cm/molecule-sec at 25 °C which corresponds to an atmospheric half-life of about 2.3 hrs at an atmospheric concn of 5X10+5 hydroxyl radicals per cu cm(1,SRC). Photodecomposition of fenuron saturated on paper was exhibited at wavelengths <280 nm(2). In the same study, a visible change in color occurred within 2 hours of exposure to sunlight indicating the importance of photodecomposition under field conditions(2). Possible photodecomposition products are aniline, o-amino-N,N-dimethylbenzamide and p-amino-N,N-dimethyl benzamide(3). Hydrolysis will not be important(SRC).

Used as herbicide to control woody plants and perennial weeds (especially on non-crop land); [HSDB]

Farming (Pesticides) [Category: Industry]

Weed and brush killer.

Herbicide

Control of woody plants and deep rooted perennial weeds, particularly on non crop land. Often used in combination with chloropropham to extend the weed spectrum and range of crops.

May be supplied in combination with other herbicides such as chlorpropham or propham. Also supplied as the salt of trichloroacetic acid.

Croptex Chrome, Croptex Ruby, Red, Herbon Yellow (fenuron + chloropropham); Electrum (20 g fenuron + 240 g chloridazon + 30 g chloropropham + 120 g propham/l); Gold, Premalox, Quintex (fenuron + chlroopropham + propham/l)

Wettable powder

All Other Chemical Product and Preparation Manufacturing

Urea, N,N-dimethyl-N'-phenyl-: ACTIVE