Trifluralin

Weed control herbicide
Trifluralin[1]
Names
Preferred IUPAC name
2,6-Dinitro-N,N-dipropyl-4-(trifluoromethyl)aniline
Other names
Treflan
Identifiers
CAS Number
  • 1582-09-8 checkY
3D model (JSmol)
  • Interactive image
ChEBI
  • CHEBI:35027 ☒N
ChEMBL
  • ChEMBL31970 checkY
ChemSpider
  • 5368 checkY
ECHA InfoCard 100.014.936 Edit this at Wikidata
KEGG
  • C14343 checkY
PubChem CID
  • 5569
UNII
  • C8BX46QL7K checkY
CompTox Dashboard (EPA)
  • DTXSID4021395 Edit this at Wikidata
InChI
  • InChI=1S/C13H16F3N3O4/c1-3-5-17(6-4-2)12-10(18(20)21)7-9(13(14,15)16)8-11(12)19(22)23/h7-8H,3-6H2,1-2H3 checkY
    Key: ZSDSQXJSNMTJDA-UHFFFAOYSA-N checkY
  • InChI=1/C13H16F3N3O4/c1-3-5-17(6-4-2)12-10(18(20)21)7-9(13(14,15)16)8-11(12)19(22)23/h7-8H,3-6H2,1-2H3
    Key: ZSDSQXJSNMTJDA-UHFFFAOYAB
  • [O-][N+](=O)c1cc(cc([N+]([O-])=O)c1N(CCC)CCC)C(F)(F)F
Properties
Chemical formula
 C13H16F3N3O4
Molar mass 335.283 g·mol−1
Appearance Yellow crystals
Melting point 46 to 47 °C (115 to 117 °F; 319 to 320 K)
Boiling point 139 to 140 °C (282 to 284 °F; 412 to 413 K) (at 4.2 mmHg)
Solubility in water
 0.0024 g/100 mL
Hazards
Lethal dose or concentration (LD, LC):
LD50 (median dose)
 >5000 mg/kg (rat, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Infobox references
Chemical compound


Trifluralin is a commonly used pre-emergence herbicide. With about 14 million pounds (6,400 t) used in the United States in 2001,[2] and 3–7 million pounds (1,400–3,200 t) in 2012,[3] it is one of the most widely used herbicides. Introduced in 1964, Trifluralin was the first organofluorine compound used as an agrochemical.[4]

Trifluralin is generally applied to the soil to control annual grass and broadleaf weed species. It inhibits root development by interrupting mitosis and thus can control weeds as they germinate.[5] Trifluralin is also used in Australia, to be applied at 0.8-3.0 L/ha (for a 480 g/L formulation).[6]

Discovery

Selective herbicides were unavailable in the 1950s to protect soybean and cotton (2,4-DNP could have been used but had to be exactingly applied lest it destroy the crops), so Lilly Research Laboratories screened ~2000 compounds from 1958 to 1980 blindly looking for a result. Trifluralin was initially thought a failure, yet the plots stayed free of weeds weeks later.[4] Application by incorporation into the top soil instead was eight times more potent.[7] Pre-plant soil incorporation was a new technique at the time. It is unclear why trifluralin's exotic 4-trifluoromethyl was tested so early (1960), before more common candidates such as fluoro, bromo, or iodo.[4]

Environmental regulation

Trifluralin has been banned in the European Union since 20 March 2008, primarily due to high toxicity to aquatic life.[8]

Trifluralin is on the United States Environmental Protection Agency list of Hazardous Air Pollutants as a regulated substance under the Clean Air Act.[9]

Environmental behavior

Trifluralin breaks down into many products as it degrades, ultimately being incorporated into soil-bound residues or converted to carbon dioxide (mineralized). Among the more unusual behaviors of trifluralin is inactivation in wet soils. This has been linked to transformation of the herbicide by reduced soil minerals, which in turn had been previously reduced by soil microorganisms using them as electron acceptors in the absence of oxygen. This environmental degradation process has been reported for many structurally related herbicides (dinitroanilines) as well as a variety of explosives such as TNT and picric acid.[10]

Trifluralin has a long half-life in soil of ~180 days, but it is accepted at high application rates because of its low soil mobility and high volatility.[4] It is safe for mammals and chickens, even in large amounts.[11]

Technical grade trifluralin crystals

Trade names

  • Trifluralin
  • Treflan
  • Trilin
  • Trust
  • Tri-4
  • Edge
  • Snapshot (formulation of isoxaben and trifluralin)

References

  1. ^ Merck Index, 11th Edition, 9598.
  2. ^ 2000-2001 Pesticide Market Estimates, United States Environmental Protection Agency
  3. ^ "Pesticides Industry Sales and Usage 2008 – 2012 Market Estimates" (PDF).
  4. ^ a b c d Epp, Jeffery B.; Schmitzer, Paul B.; Crouse, Gary D. (4 July 2017). "Fifty years of herbicide research: comparing the discovery of trifluralin and halauxifen-methyl". Pest Management Science. Retrieved 6 August 2024.
  5. ^ Grover, Raj; Wolt, Jeffrey D.; Cessna, Allan J.; Schiefer, H. Bruno (1997). "Environmental Fate of Trifluralin". Reviews of Environmental Contamination and Toxicology. Vol. 153. pp. 1–64. doi:10.1007/978-1-4612-2302-3_1. ISBN 978-1-4612-7492-6. PMID 9380893.
  6. ^ "Trifluralin 480 Leaflet" (PDF). 4farmers.com.au. 4Farmers Australia. Retrieved 28 May 2024.
  7. ^ Anderson, W. Powell; Richards, Anna Beth; Whitworth, J. Wayne (Jul 1967). "Trifluralin Effects On Cotton Seedlings". Weeds. 15 (3): 224–227. Retrieved 6 August 2024.
  8. ^ "European Union - Final Regulatory Action".
  9. ^ "Initial List of Hazardous Air Pollutants with Modifications". United States Environmental Protection Agency. 16 December 2015. Retrieved 16 December 2021.
  10. ^ Tor, Jason M.; Xu, Caifen; Stucki, Joseph M.; Wander, Michelle M.; Sims, Gerald K. (2000). "Trifluralin Degradation under Microbiologically Induced Nitrate and Fe(III) Reducing Conditions". Environmental Science & Technology. 34 (15): 3148–3152. Bibcode:2000EnST...34.3148T. doi:10.1021/es9912473.
  11. ^ Worth, H. M.; Anderson, R. C. (1965). "The toxicity of trifluralin, Treflan, an herbicide, to mammals and chickens". SWC. 18: 711–712.
  • Trifluralin in the Pesticide Properties DataBase (PPDB)
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