Swep
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| Names | |
|---|---|
| Preferred IUPAC name
Methyl N-(3,4-dichlorophenyl)carbamate[1] | |
| 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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| |
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| Properties | |
| C8H7Cl2NO2 | |
| Molar mass | 220.05 g·mol−1 |
| Appearance | White crystals[1] |
| Melting point | 110 °C (230 °F; 383 K) [4] |
| Vapor pressure | 187 mPa[5] |
| Hazards | |
| GHS labelling:[1] | |
 | |
| 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) |
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).
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Swep or MCC is a carbamate herbicide discovered in the 1960s,[2] formerly used to control annual weeds and grasses in rice, potatoes, cotton, corn, peas, peanuts, and sorghum, and is no longer used in the US[3] 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
[edit]Swep interferes with cell division and growth.[6]
Environmental behaviour
[edit]Swep is relatively volatile, with a vapour pressure of 187 mPa, so swep can be lost to the atmosphere.[5] 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.[4]
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).[4] 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.[4]
Uses
[edit]Swep is usually formulated as an emulsifiable concentrate (EC).[2]
Swep can control grasses, broadleaf weeds, and sedges,[2] including barnyard grass, purslane, chenopodium and trifoliate grass.[5]
It is used on cereals and vegetables[2] including leek, green onion and garlic.[5]
References
[edit]- 1 2 3 4 5 6 7 "methyl N-(3,4-dichlorophenyl)carbamate". pubchem.ncbi.nlm.nih.gov. PubChem. Retrieved 9 February 2026.
- 1 2 3 4 5 Hertfordshire, University of. "Swep". sitem.herts.ac.uk. Pesticide Properties Database. Retrieved 9 February 2026.
- 1 2 "Swep - Hazardous Agents | Haz-Map". haz-map.com. Retrieved 9 February 2026.
- 1 2 3 4 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. Bibcode:1969BuECT...4..240B. doi:10.1007/BF01557982. PMID 24185499. Retrieved 9 February 2026.
- 1 2 3 4 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. Bibcode:2022ScTEn.81651651A. doi:10.1016/j.scitotenv.2021.151651. PMID 34785220. Retrieved 9 February 2026.
- 1 2 3 4 5 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. PMID 31910844.
External links
[edit]- Swep in the Pesticide Properties DataBase (PPDB)