SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 33245395
CASRN 33245-39-5
SynonymsFluchloralin
Basalin
p-Toluidine, N-(2-chloroethyl)-2,6-dinitro-N-propyl-alpha,alpha,alpha-trifluoro-
Analytical Method EPA Method 646
Molecular FormulaC12H13ClF3N3O4

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use HERBICIDE SRP: FORMER USE
Apparent Color ORANGE-YELLOW CRYSTALLINE SOLID
Odor FAINT, MEDICINAL ODOR
Melting Point 42-43 DEG C
Molecular Weight 355.70
Sensitivity Data MAY CAUSE SLIGHT REDDENING TO SKIN AND EYES.
Environmental Impact Fluchloralin's use as a pre-plant or pre-emergence herbicide releases the compound directly to the environment through applications in sprays and other routes of application. If released to the atmosphere, fluchloralin will degrade rapidly in the vapor-phase by reaction with photochemically produced hydroxyl radicals (half-life of about 5 hr). If applied to soil surfaces, fluchloralin can dissipate rapidly through photodecomposition and volatilization; half-lives of 1.5-4.0 days have been observed following surface application; however, immediate soil incorporation greatly increases soil persistence. Various persistence studies have reported fluchloralin soil half-lives ranging from several weeks to several months. Within soil systems, biodegradation is the probable route of disappearance, but it appears to be much slower than surface photolysis or volatilization. Under field conditions, fluchloralin has not been found to leach. If released to water, fluchloralin can degrade through photodecomposition and biodegradation. Volatilization may contribute to its loss from water. Occupational exposure occurs through dermal contact and inhalation of sprays, especially to workers applying the compound as a herbicide. Since fluchloralin has been detected infrequently in U.S. foods, exposure to the general population through consumption of foods containing fluchloralin residues would appear to be slight.
Environmental Fate C-Fluchloralin was degraded in a loamy sand soil. Degradation products were identified by TLC and GLC and comparison with standard compounds whose structure was confirmed by IR and MS. Degradation products included the following compounds: N-(2-chloroethyl)-2,6-dinitro-4-trifluoromethylaniline, 2,6-dinitro-4-trifluoromethylphenol, 2,6-dinitro-4-trifluoromethylaniline, 1,2-diamino-6-nitro-4-trifluoromethylbenzene, 1,2,3-triamino-5-trifluoromethylbenzene, 2,6-dinitro-N-(2-hydroxypropyl)-N-propyl-4-trifluoromethylaniline, 2,6-dinitro-N-propyl-4-trifluoromethylaniline. Some CO was formed and a part of the (l4)C was found in humic acids. TERRESTRIAL FATE: Fluchloralin can dissipate readily from soil surfaces through volatilization and photodegradation. One study found a half-life of 1.5-4.0 days following surface application . Screening studies have demonstrated that fluchloralin photolyzes(2-3) and volatilizes readily from near surface soil(4-5). Within soil, fluchloralin appears to biodegrade; grab sample tests have shown that fluchloralin degrades faster in nonsterile soil than in sterile soil(6); however, the rate appears to be much slower than surface photodecomposition or volatilization. For example, at recommended rates of application, low levels of fluchloralin residues can persist for more than one season after application(7). Under field conditions, fluchloralin has not been found to leach(7). TERRESTRIAL FATE: The results of field and laboratory studies conducted over a 3-yr period found that delaying soil incorporation of herbicidal applications of fluchloralin caused important herbicide losses through volatilization and photodecomposition ; avg losses for delayed incorporation for 1, 3 and 7 days were 11, 29, and 69% respectively . In greenhouse studies using a silt loam and a clay loam soil, fluchloralin had a half-life of 3.3 to 5.1 months . In laboratory soil metabolism studies, fluchloralin metabolites were found to include a benzimidazole derivative, a quinoxaline derivative and various fluchloralin dealkylation derivatives . A field study in Arkansas found half-lives of 12.2-17.6 weeks ; a laboratory study at 25 deg C found half-lives of 8.4 weeks (field capacity) and 2.9 weeks (flooded conditions) ; at 4 deg C, half-lives were 28.7 weeks (field capacity) and 19.5 weeks (flooded conditions) . In 2-yr Wisconsin field tests, initial half-lives of about 60-75 days were observed ; in greenhouse tests, persistence was much greater in dry soil (half-life >29-55 days) than in wet soil (63% dissipation in 29 days) . AQUATIC FATE: Fluchloralin can degrade in natural water through photodecomposition and biodegradation. In one aqueous photolysis study , 84% of initial fluchloralin photolyzed after 13 days of natural sunlight exposure ; other aqueous photolysis tests have also found rapid photodegradation . Biological screening tests have found fluchloralin to be biodegradable ; however, sufficient data are not available to predict the rate or its relative environmental importance in water. Volatilization may contribute to fluchloralin/s!dissipation from water; in the absence of strong adsorption to sediment, volatilization half-lives of 35 hr and 16 days can be estimated for a model river (1 m deep) and a model pond (2 m deep), respectively(4-5,SRC). Koc values ranging from 200 to 3600(6-7,SRC) indicate some adsorption to sediment may occur which will decrease volatilization rates. ATMOSPHERIC FATE: Based upon a reported vapor pressure of 2.1X10-5 mm Hg at 20 deg C , fluchloralin can exist in both the vapor and particulate-phases in the ambient atmosphere, although the vapor-phase will dominate(2,SRC). It will degrade rapidly in the vapor-phase by reaction with photochemically produced hydroxyl radicals with an estimated half-life of about 5 hr(3,SRC). Particulate-phase fluchloralin and aerosols released to air during applications of fluchloralin herbicides will be physically removed from air by dry and wet deposition.

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