Swep

Swep
Names
Preferred IUPAC name
Methyl N-(3,4-dichlorophenyl)carbamate[3]
Other names
  • MCC[1]
  • FMC 2995
  • NIA 2995J
  • Methyl 3,4-dichlorocarbanilate
  • Methyl 3,4-dichlorophenylcarbamate
  • Methyl N-(3,4-dichlorophenyl)carbamate
  • 3,4-Dichlorocarbanilic acid methyl ester
  • Carbamic acid, (3,4-dichlorophenyl)-, methyl ester[2]
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ECHA InfoCard 100.149.159
EC Number
  • 620-362-9
KEGG
UNII
  • InChI=1S/C8H7Cl2NO2/c1-13-8(12)11-5-2-3-6(9)7(10)4-5/h2-4H,1H3,(H,11,12)
    Key: WOZQBERUBLYCEG-UHFFFAOYSA-N
  • COC(=O)NC1=CC(=C(C=C1)Cl)Cl
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):
522 mg/kg (rat, oral)[6]
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

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

  1. ^ a b c d e Hertfordshire, University of. "Swep". sitem.herts.ac.uk. Pesticide Properties Database. Retrieved 9 February 2026.
  2. ^ a b "Swep - Hazardous Agents | Haz-Map". haz-map.com. Retrieved 9 February 2026.
  3. ^ a b c d e f g "methyl N-(3,4-dichlorophenyl)carbamate". pubchem.ncbi.nlm.nih.gov. PubChem. Retrieved 9 February 2026.
  4. ^ 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.
  5. ^ 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.
  6. ^ 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.
  • Swep in the Pesticide Properties DataBase (PPDB)