Swep

Swep
Names
Preferred IUPAC name
Methyl N-(3,4-dichlorophenyl)carbamate
Other names
  • MCC
  • 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
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ECHA InfoCard 100.149.159 Edit this at Wikidata
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
Melting point 110 °C (230 °F; 383 K)
Vapor pressure 187 mPa
Hazards
GHS labelling:
GHS07: Exclamation mark
H302
P264, P270, P301+P317, P330, P501
Lethal dose or concentration (LD, LC):
522 mg/kg (rat, oral)
2.6 mg/L (carp, 48 hour)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Swep or MCC is a carbamate herbicide discovered in the 1960s, 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 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.).

Mechanism of action

Swep interferes with cell division and growth.

Environmental behaviour

Swep is relatively volatile, with a vapour pressure of 187 mPa, so swep can be lost to the atmosphere. 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.

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). 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. DCA is an intermediate, and does not accumulate in meaningful quantities are swep decomposes.

Uses

Swep is usually formulated as an emulsifiable concentrate (EC).

Swep can control grasses, broadleaf weeds, and sedges, including barnyard grass, purslane, chenopodium and trifoliate grass.

It is used on cereals and vegetables including leek, green onion and garlic.

References

  1. 1 2 3 4 5 6 7 "methyl N-(3,4-dichlorophenyl)carbamate". pubchem.ncbi.nlm.nih.gov. PubChem. Retrieved 9 February 2026.
  2. 1 2 3 4 5 Hertfordshire, University of. "Swep". sitem.herts.ac.uk. Pesticide Properties Database. Retrieved 9 February 2026.
  3. 1 2 "Swep - Hazardous Agents | Haz-Map". haz-map.com. Retrieved 9 February 2026.
  4. 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.
  5. 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.
  6. 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.