Article · Wikipedia archive · Last revised Aug 6, 2026

Isopropalin

Isopropalin is a herbicide. Introduced in 1969, it is a preëmergent selective dinitroaniline to control annual grasses and broadleaf weeds. Brought by DowElanco in 1972 to the US and Australia, it is now considered obsolete. In 1974, American farmers used 250,000 pounds (110,000 kg) of isopropalin.

Last revised
Aug 6, 2026
Read time
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Citations
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Source
Wikipedia ↗

Isopropalin
source ↗
Names
Preferred IUPAC name
4-Isopropyl-2,6-dinitro-N,N-dipropylaniline
Other names
  • Paarlan
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.046.977
EC Number
  • 251-690-7
KEGG
UNII
  • InChI=1S/C15H23N3O4/c1-5-7-16(8-6-2)15-13(17(19)20)9-12(11(3)4)10-14(15)18(21)22/h9-11H,5-8H2,1-4H3
    Key: NEKOXWSIMFDGMA-UHFFFAOYSA-N
  • CCCN(CCC)C1=C(C=C(C=C1[N+](=O)[O-])C(C)C)[N+](=O)[O-]
Properties
C15H23N3O4
Molar mass 309.366 g·mol−1
Appearance Orange liquid1
0.11ppm2
Vapor pressure 30 × 10−6 mm Hg (30°C)2
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Toxic to fish
GHS labelling:34
GHS05: CorrosiveGHS09: Environmental hazard
Warning
H226, H410
P210, P233, P240, P241, P242, P243, P273, P280, P303+P361+P353, P370+P378, P391, P403+P235, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Isopropalin is a herbicide. Introduced in 1969, it is a preëmergent selective dinitroaniline to control annual grasses and broadleaf weeds. Brought by DowElanco in 1972 to the US and Australia, it is now considered obsolete.156 In 1974, American farmers used 250,000 pounds (110,000 kg) of isopropalin.7

Paarlan was a 69% isopropalin emulsifiable concentrate5 approved for use on tobacco.3 It required soil incorporation due to low solubility, ultraviolet light degradation and high volatilisation, and it may have been registered for white potatoes and tomatoes.8 Dow marketed Paarlan to southern culture, with a video advert claiming it "is just as much a part of tobacco country as ham and biscuits are part of breakfast."9

Rats fed diets with large amounts of isopropalin had reduced hemoglobin concentrations, lowered hematocrits, and altered organ weights at the higher doses tested.10

Isopropalin is the most persistent dinitroaniline herbicide in soil, with a field halflife of nearly 10 months, though only 6 months in the greenhouse test. It is one of the least phytotoxic to sorghum, though in weed-control tests had roughly middle of the pack phytotoxicity to weeds.11

References

References

  1. "Isopropalin (Ref: EL-179)". sitem.herts.ac.uk.
  2. Huffman, J. B.; Camper, N. D. (1978). "Growth Inhibition in Tobacco (Nicotiana tabacum) Callus by 2,6-Dinitroaniline Herbicides and Protection by D-α-Tocopherol Acetate". Weed Science. 26 (6): 527–530. Bibcode:1978WeedS..26..527H. doi:10.1017/S0043174500064468. ISSN 0043-1745.
  3. "Label Amendment Submission of 08/30/93 in Response to PR Notice 93-7" (PDF). search.epa.gov. EPA. 1993.
  4. "Isopropalin". pubchem.ncbi.nlm.nih.gov.
  5. "Paarlan Herbicide Emulsifiable Concentrate" (PDF). search.epa.gov. Elanco. 1975.
  6. "Paarlan, An Australia Trademark of DowElanco. Application Number: 255181 :: Trademark Elite Trademarks". www.trademarkelite.com.
  7. "Pesticide Usage Survey of Agricultural, Governmental, and Industrial Sectors in the United States, 1974". epa.gov. EPA. 1977.
  8. Ford, D. H.; Massey, G. D. "Characteristics of the Substituted Dinitroaniline Herbicides, Treflan, Balan, Paarlan, and EL-119".
  9. "Paarlan and Tobacco Country USA". NDSU Extension Pesticide Program. 27 January 2023. Retrieved 23 October 2024.
  10. "Isopropalin CASRN 33820-53-0 | DTXSID8024157 | IRIS". cfpub.epa.gov. Archived from the original on 7 January 2017.
  11. Stoller, E. W.; Wax, L. M. (1977). "Persistence and Activity of Dinitroaniline Herbicides in Soil". Journal of Environmental Quality. 6 (2): 124–127. Bibcode:1977JEnvQ...6..124S. doi:10.2134/jeq1977.00472425000600020004x.
  • Isopropalin in the Pesticide Properties DataBase (PPDB)