Chemistry:Isopropalin
Isopropalin is a herbicide. Invented 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.[1][2][3] In 1974, American farmers used 250,000 pounds (110,000 kg) of isopropalin.[4]
Paarlan
Paarlan was a 69% isopropalin emulsifiable concentrate[2] approved for use on tobacco.[5] 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.[6] 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."[7]
Paarlan was applied at 1-2 kg/Ha (active ingredient).[8]
Safety
Rats fed diets with large amounts of isopropalin had reduced hemoglobin concentrations, lowered hematocrits, and altered organ weights at the higher doses tested.[9] It is slightly irritating to skin and eyes. Its NOEL on dogs is over 250 mg/kg dietary.[8]
Environmental behaviour
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.[10]
Isopropalin is not toxic to chickens, mallard ducks, (LD50 >2000 mg/kg) or quail (>1000 mg/kg). The LC50 for goldfish is >0.15 mg/L, for minnows, >0.1 mg/L.[8]
It does not translocate, in plants, to the leaves or fruit, and no significatn residues or metabolites have been detected. Isopropalin is strongly absorbed in soil, with minimal leaching, and a soil half-life of under 6 months. The loss in soil is possibly from microörgamisms, volatilisation and photolysis of ispropalin on the surface.[8]
Chemical properties
Isopropalin is only one part in a million soluble in water, but dissolves readily, to more than 1000 g/L, in acetone, hexane, benzene, chloroform, diethyl ether, acetonitrile and methanol. It is stable in field use, but decomposes in laboratory under UV light.[8]
References
- ↑ Cite error: Invalid
<ref>tag; no text was provided for refs nameddatabase - ↑ 2.0 2.1 "Paarlan Herbicide Emulsifiable Concentrate". Elanco. 1975. https://www3.epa.gov/pesticides/chem_search/ppls/001471-00079-19751103.pdf.
- ↑ "Paarlan, An Australia Trademark of DowElanco. Application Number: 255181 :: Trademark Elite Trademarks" (in en). https://www.trademarkelite.com/australia/trademark/trademark-detail/255181/PAARLAN.
- ↑ "Pesticide Usage Survey of Agricultural, Governmental, and Industrial Sectors in the United States, 1974". EPA. 1977. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=91012P4O.txt.
- ↑ "Label Amendment Submission of 08/30/93 in Response to PR Notice 93-7". EPA. 1993. https://www3.epa.gov/pesticides/chem_search/ppls/062719-00104-19931202.pdf.
- ↑ Ford, D. H.; Massey, G. D.. "Characteristics of the Substituted Dinitroaniline Herbicides, Treflan, Balan, Paarlan, and EL-119". https://ucanr.edu/repository/fileaccess.cfm?article=163966&p=WRRCUA.
- ↑ "Paarlan and Tobacco Country USA" (in en). NDSU Extension Pesticide Program. 27 January 2023. https://vimeo.com/793368419.
- ↑ 8.0 8.1 8.2 8.3 8.4 Macbean, C. (2012). A World Compendium The Pesticide Manual (16th ed.). Hampshire, UK: British Crop Protection Council. ISBN 978 1 901396 86 7.
- ↑ "Isopropalin CASRN 33820-53-0 | DTXSID8024157 | IRIS" (in en). https://cfpub.epa.gov/ncea/iris2/chemicalLanding.cfm?substance_nmbr=64.
- ↑ Stoller, E. W.; Wax, L. M. (1977). "Persistence and Activity of Dinitroaniline Herbicides in Soil". Journal of Environmental Quality 6 (2): 124–127. doi:10.2134/jeq1977.00472425000600020004x. Bibcode: 1977JEnvQ...6..124S.
Links
- Isopropalin in the Pesticide Properties DataBase (PPDB)
 |  |
