Diflufenican
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| Names | |
|---|---|
| IUPAC name
N-(2,4-difluorophenyl)-2-[3-(trifluoromethyl)phenoxy]pyridine-3-carboxamide
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| Other names
diflufenicanil; N-(2,4-Difluorophenyl)-2-(3-(trifluoromethyl)phenoxy)nicotinamide
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| Identifiers | |
| ChemSpider | |
| ECHA InfoCard | 100.122.360 |
PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| C19H11F5N2O2 | |
| Molar mass | 394.301 g·mol−1 |
| Appearance | White Powder |
| Density | 1.438 g/cm3[1] |
| Melting point | 160[2][1] °C (320 °F; 433 K) |
| Boiling point | 376[1] °C (709 °F; 649 K) |
| Insoluble[2] - 0.05mg/L[3] | |
| Solubility in acetone | Soluble[2] - 100 g/L[3] |
| Solubility in ethylene glycol | Soluble[4] |
| Solubility in ethanol | Soluble[4] |
| Vapor pressure | 0.07 mPa (30°C)[3] |
| Hazards | |
| GHS labelling: | |
 [5]
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| H411, H413[5] | |
| P262, P273, P352, P391[5] | |
| Flash point | 181.3°C, 358.3°F[1] |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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>5000 mg/kg (rat, oral)[2] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Diflufenican (sometimes called DFF) is a herbicide used to control weeds including wild radish and wild turnip weeds or suppress capeweed, crassula, marshmallow or shepherd's purse, in clover pasture, lupins, lentils or field peas. It has seen use in Australia,[6] Europe, and in Feb 2024 registered in North America by the PMRA, EPA registration pending, for use on soybean and corn.[7]
Diflufenican is often applied at 50-100 g/ha,[8][6] or lower if part of a herbicide mixture, e.g. as little as 9 g/ha with bromoxynil.[9]
Discovery
[edit]Diflufenican was discovered with a common intermediate method (CIM),[10] and trialled in England and France between 1981-1983.[11] A simple intermediate is reacted and recombined. Diflufenican derives from 2-chloronicotinic acid, one product replaced the chlorine with a phenoxy group, one receives an aniline group, and then both are recombined into DFF.[10]
Toxicology
[edit]The Australian Acceptable Daily Intake for diflufenican is set at 0.2 mg/kg/day, based on the NOEL of 16.3 mg/kg/day.[5] With an oral rat LD50 of >5000 mg/kg, diflufenican is not toxic to mammals,[2] nor to honeybees.[7][3]
By inhalation, the air LC50 is 2.34 mg/L, for rats. It is not irritating to the skin and eyes, tested on rabbits. In dogs over 90 days, a NOEL of 1000 mg/kg daily was found. By the Ames Test, it is non-mutagenic.[3]
To birds, diflufenican is not toxic. LD50 of >2150 mg/kg (quail), >4000 mg/kg (mallard ducks). For fish, the LC50 is 56-100 mg/L (rainbow trout), 105 mg/L (carp). DFF does not inhibit the growth of algae. Non-toxic to earthworms.[3]
Environmental Fate
[edit]Diflufenican has high persistence in soil but has low mobility, and low bioaccumulative potential. It is toxic to aquatic life.[5] (See toxicology section for details).
Diflufenican rapidly metabolises in cereals to carbon dioxide via nicotinamide and nicotinic acid, and leaves no detectable residue after 200-250 days. In soil, similar degradation to CO2 is seen, with a half life of 15 to 30 weeks.[3]
Effect and Mechanism
[edit]Targeted weeds display bleaching and chlorotic spotting, followed by pink and purple foliage and necrosis. Symptoms typically begin 3–4 days after application.[6] DFF's residual activity may last 8 weeks.[8]
Diflufenican inhibits carotenoid synthesis, without which photosynthesis begins to fail and the plant is vulnerable to damage from sunlight, causing growth cessation and necrosis.[7] It is absorbed by germinating seedlings. Usually applied at 125-250 g/ha pre-emergence or shortly after, often with other cereal herbicides.[3]
List of Applications
[edit]Diflufenican has shown control over: wild radish, wild turnip, turnip weed,[6] multiply herbicide resistant waterhemp[7] (applied pre-emergence), hedge mustard, Indian hedge mustard, charlock, deadnettle, prickly lettuce, pheasant's eye,[8] Galium aparine, ivy-leaved speedwell and Veronica persica;[11] and suppression of capeweed, crassula, night-scented stock, marshmallow, corn gromwell, chickweed, hyssop loosestrife, Skeleton weed, speedwell, amsinckia, Paterson's curse, rough poppy, sorrel, toad rush, stinging nettle and shepherd's purse.[8]
Diflufenican has been sold in formulations containing (not limited to): isoproturon, ioxynil, mecoprop, bromoxynil and diclofop-methyl.[3] Furthermore, compatibility is reported with: simazine, alpha cypermethrin, metribuzin and quizalofop, in addition to compatibility with most grass herbicides.[8]
Diflufenican has been applied to crops, including: wheat, barley,[3], field peas, lentils, lupins and oilseed poppy.[8]
Trade Names
[edit]- Diflufenican
- DFF
- Brodal
References
[edit]- ^ a b c d "Diflufenican Safety Data Sheets". EChemi.
- ^ a b c d e "Diflufenican Standard SDS" (PDF). FujiFilm. Retrieved 7 August 2024.
- ^ a b c d e f g h i j Tomlin, Clive (1994). The Pesticide Manual Incorporating the Agrochemicals Handbook (Tenth ed.). State Library of Western Australia: The Royal Society of Chemistry. p. 335. ISBN 0-948404-79-5.
- ^ a b Li, Wentian; Wang, Juan; Li, Shuguang; Liu, Yinping; Li, Siqi; Wu, Junfeng (2023). "Solubility modeling, dissolution and solvation thermodynamics, and solute–solvent interactions of diflufenican in aqueous aprotic and protic cosolvents". The Journal of Chemical Thermodynamics. 179: 106981. doi:10.1016/j.jct.2022.106981.
- ^ a b c d e "4Farmers Diflufenican 500 SDS" (PDF). 4Farmers Australia.
- ^ a b c d "4Farmer Diflufenican 500 Infosheet" (PDF). 4Farmers Australia.
- ^ a b c d Soltani, Nader; Willemse, Christian; Sikkema, Peter H. (3 June 2024). "Biologically effective dose of diflufenican applied preemergence for the control of multiple herbicide-resistant waterhemp in corn" (pre-proof). Weed Technology. doi:10.1017/wet.2024.42.
- ^ a b c d e f "4Farmers Diflufenican 500 Label" (PDF). 4Farmers Australia. Retrieved 7 August 2024.
- ^ "4Farmers Bromoxynil DFF Label" (PDF). 4farmers.com.au. 4Farmers Australia. Retrieved 28 August 2024.
- ^ a b Changling, Liu; Guan, Aiying; Yang, Jindong (17 December 2014). "Efficient Approach To Discover Novel Agrochemical Candidates: Intermediate Derivatization Method". Journal of Agricultural and Food Chemistry. 64 (1). doi:10.1021/jf5054707.
- ^ a b Cramp, Michael C.; Gilmour, James; Hatton, Leslie R.; Hewett, Richard H.; Duck, Donald; Nolan, Christopher J.; Parnell, Edgar W. (30 Oct 1985). "Design and Synthesis of N-(2,4-difluoropheny1)-2-(3-trifluoromethylphenoxy)-3-pyridinecarboxamide (diflufenican), a Novel Pre- and Early Post-emergence Herbicide for Use in Winter Cereals". Pesticide Science. 18: 15–28. doi:10.1002/ps.2780180103.
External Links
[edit]- Diflufenican in the Pesticide Properties DataBase (PPDB)