Swep
| Names | |
|---|---|
| Preferred IUPAC name
Methyl N-(3,4-dichlorophenyl)carbamate[3] | |
| Other names | |
| Identifiers | |
3D model (JSmol)
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| ChEBI | |
| ChEMBL | |
| ECHA InfoCard | 100.149.159 |
| EC Number |
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| KEGG | |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C8H7Cl2NO2 | |
| Molar mass | 220.05 g·mol−1 |
| Appearance | White crystals[3] |
| Melting point | 110 °C (230 °F; 383 K) [5] |
| Vapor pressure | 187 mPa[4] |
| Hazards | |
| GHS labelling:[3] | |
| H302 | |
| P264, P270, P301+P317, P330, P501 | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
|
522 mg/kg (rat, oral)[6] |
LC50 (median concentration)
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2.6 mg/L (carp, 48 hour)[6] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
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Swep or MCC is a carbamate herbicide discovered in the 1960s,[1] formerly used to control annual weeds and grasses in rice, potatoes, cotton, corn, peas, peanuts, and sorghum, and is no longer used in the USA.[2] Notably, swep must be applied at high rates per acre compared to other herbicides, 3.75-5.62 kg/Ha (3.35-5.01 lbs/ac.).[6]
Mechanism of action
Swep interferes with cell division and growth.[6]
Environmental behaviour
Swep is relatively volatile, with a vapour pressure of 187 mPa, so swep can be lost to the atmosphere.[4] In a laboratory soil degradation test, the amount of swep in soil halved in 21 days. Degradation is by microbial breakdown, not by chemical means.[5]
3,4-Dichloroaniline (DCA) is swep's primary metabolite, roughly one part in six of which is further transformed to 3,3',4,4'-tetrachloroazobenzene (TCAB).[5] DCA can be broken down (mineralised) by many microbes, including strains of variovorax, sphingomonas and achromobacter. A "consortium" of a couple of bacteria strains can convert swep to DCA and then break down the 3,4-DCA.[6] DCA is an intermediate, and does not accumulate in meaningful quantities are swep decomposes.[5]
Uses
Swep is usually formulated as an emulsifiable concentrate (EC).[1]
Swep can control grasses, broadleaf weeds, and sedges,[1] including barnyard grass, purslane, chenopodium and trifoliate grass.[4]
It is used on cereals and vegetables[1] including leek, green onion and garlic.[4]
References
- ^ a b c d e Hertfordshire, University of. "Swep". sitem.herts.ac.uk. Pesticide Properties Database. Retrieved 9 February 2026.
- ^ a b "Swep - Hazardous Agents | Haz-Map". haz-map.com. Retrieved 9 February 2026.
- ^ a b c d e f g "methyl N-(3,4-dichlorophenyl)carbamate". pubchem.ncbi.nlm.nih.gov. PubChem. Retrieved 9 February 2026.
- ^ a b c d An, Zexiu; Bo, Xiaofei; Mei, Qiong; Wei, Bo; Xie, Ju; Zhan, Jinhua; He, Maoxia (10 April 2022). "Theoretical insights into the degradation of swep by hydroxyl radicals in atmosphere and water environment: Mechanisms, kinetics and toxicity". Science of The Total Environment. 816 151651. doi:10.1016/j.scitotenv.2021.151651. Retrieved 9 February 2026.
- ^ a b c d Bartha, R.; Pramer, D. (July 1969). "Transformation of the herbicide methyl-N-(3,4-dichlorophenyl)-carbamate (Swep) in soil". Bulletin of Environmental Contamination and Toxicology. 4 (4): 240–245. doi:10.1007/BF01557982. Retrieved 9 February 2026.
- ^ a b c d e Zhang, Long; Hang, Ping; Zhou, Xiyi; Dai, Chen; He, Ziyi; Jiang, Jiandong (7 January 2020). "Mineralization of the herbicide swep by a two-strain consortium and characterization of a new amidase for hydrolyzing swep". Microbial Cell Factories. 19 (1): 4. doi:10.1186/s12934-020-1276-9. PMC 6945715. Retrieved 9 February 2026.
External links
- Swep in the Pesticide Properties DataBase (PPDB)