isopropalin

{{Short description|Weed control herbicide}}

{{Chembox

| Reference =

| ImageFile = Isopropalin.svg

| PIN = 4-Isopropyl-2,6-dinitro-N,N-dipropylaniline

| OtherNames = {{ubl|Paarlan|}}

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 33636

| KEGG_Ref = {{keggcite|changed|kegg}}

| KEGG = C19063

| ChEBI_Ref = {{ebicite|changed|EBI}}

| EC_number = 251-690-7

| ChEBI = 82189

| ChEMBL = 1256728

| ChEMBL_Ref = {{ebicite|changed|EBI}}

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo = 33820-53-0

| PubChem = 36606

| UNII = 52GZD1I41N

| StdInChI= 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

| StdInChIKey = NEKOXWSIMFDGMA-UHFFFAOYSA-N

| SMILES = CCCN(CCC)C1=C(C=C(C=C1[N+](=O)[O-])C(C)C)[N+](=O)[O-]

}}

|Section2={{Chembox Properties

| C=15|H=23|N=3|O=4

| Appearance = Orange liquid{{cite web |title=Isopropalin (Ref: EL-179) |url=https://sitem.herts.ac.uk/aeru/ppdb/en/Reports/407.htm#none |website=sitem.herts.ac.uk}}

| Odour =

| Density =

| MeltingPtC =

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| BoilingPtF =

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| Solubility = 0.11ppm{{cite journal |last1=Huffman |first1=J. B. |last2=Camper |first2=N. D. |title=Growth Inhibition in Tobacco (Nicotiana tabacum) Callus by 2,6-Dinitroaniline Herbicides and Protection by D-α-Tocopherol Acetate |journal=Weed Science |date=1978 |volume=26 |issue=6 |pages=527–530 |issn=0043-1745}}

| Solvent1 = Acetone

| Solubility1 =

| Solvent2 = Benzene

| Solubility2 =

| Solvent3 = Acetonitrile

| Solubility3 =

| Solvent4 = Xylene

| Solubility4 =

| VaporPressure = 30x10⁻⁶ mm Hg (30°C)

}}

|Section3={{Chembox Hazards

| MainHazards = Toxic to fish

| GHS_ref={{cite web |title=Isopropalin |url=https://pubchem.ncbi.nlm.nih.gov/compound/36606#section=Safety-and-Hazards |website=pubchem.ncbi.nlm.nih.gov |language=en}}

| GHSPictograms = {{GHS05}}{{GHS09}}

| GHSSignalWord = Warning

| HPhrases = {{H-phrases|226|410}}

| PPhrases = {{P-phrases|210|233|240|241|242|243|273|280|303+361+353|370+378|391|403+235|501}}

| LD50 =

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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.{{cite web |title=Paarlan, An Australia Trademark of DowElanco. Application Number: 255181 :: Trademark Elite Trademarks |url=https://www.trademarkelite.com/australia/trademark/trademark-detail/255181/PAARLAN |website=www.trademarkelite.com |language=en}} In 1974, American farmers used {{convert|250000|lbs|kg}} of isopropalin.{{cite web |title=Pesticide Usage Survey of Agricultural, Governmental, and Industrial Sectors in the United States, 1974 |url=https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=91012P4O.txt |website=epa.gov |publisher=EPA |date=1977}}

Paarlan was a 69% isopropalin emulsifiable concentrate{{cite web |title=Paarlan Herbicide Emulsifiable Concentrate |url=https://www3.epa.gov/pesticides/chem_search/ppls/001471-00079-19751103.pdf |website=search.epa.gov |publisher=Elanco |date=1975}} approved for use on tobacco.{{cite web |title=Label Amendment Submission of 08/30/93 in Response to PR Notice 93-7 |url=https://www3.epa.gov/pesticides/chem_search/ppls/062719-00104-19931202.pdf |website=search.epa.gov |date=1993 |publisher=EPA}} 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.{{cite web |last1=Ford |first1=D. H. |last2=Massey |first2=G. D. |title=Characteristics of the Substituted Dinitroaniline Herbicides, Treflan, Balan, Paarlan, and EL-119 |url=https://ucanr.edu/repository/fileaccess.cfm?article=163966&p=WRRCUA}} 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."{{cite web |title=Paarlan and Tobacco Country USA |url=https://vimeo.com/793368419 |publisher=NDSU Extension Pesticide Program |access-date=23 October 2024 |language=en}}

Rats fed diets with large amounts of isopropalin had reduced hemoglobin concentrations, lowered hematocrits, and altered organ weights at the higher doses tested.{{cite web |title=Isopropalin CASRN 33820-53-0 {{!}} DTXSID8024157 {{!}} IRIS |url=https://cfpub.epa.gov/ncea/iris2/chemicalLanding.cfm?substance_nmbr=64 |website=cfpub.epa.gov |language=en}}

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.{{cite journal |last1=Stoller |first1=E. W. |last2=Wax |first2=L. M. |title=Persistence and Activity of Dinitroaniline Herbicides in Soil |journal=Journal of Environmental Quality |date=1977 |volume=6 |issue=2 |pages=124–127 |doi=10.2134/jeq1977.00472425000600020004x}}