Nitralin
Weed control herbicide
From Wikipedia, the free encyclopedia
Nitralin is a selective preëmergent dinitroaniline herbicide[7] that is closely related to trifluralin, and released two years later in 1966. Today it is largely obsolete. It was used in the USA, France and Australia to control annual grasses and broad-leaved weeds, and was applied on vines, crops[8][9][10] and turf.[7]
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| Names | |
|---|---|
| Preferred IUPAC name
4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline | |
Other names
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| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.022.926 |
| EC Number |
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| KEGG | |
PubChem CID |
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| UNII | |
| UN number | 3077 |
CompTox Dashboard (EPA) |
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| Properties | |
| C13H19N3O6S | |
| Molar mass | 345.37 g·mol−1 |
| Appearance | Yellow/orange powder[2][3] |
| Odor | Mild odour[3] |
| Density | 1.001[4] |
| Melting point | 151 °C (304 °F; 424 K) [2] |
| Boiling point | 225 °C; 437 °F; 498 K (decomposes)[3] |
| 0.0006 g/L[2] | |
| Solubility in acetone | Soluble[2] |
| Vapor pressure | 0.2 x10−6 mm Hg (25°C)[5] |
| Hazards | |
| GHS labelling:[2][3] | |
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| H228, H410 | |
| P273, P391, P501 | |
| 224 °C; 435 °F; 497 K | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
>5000 mg/kg[6] (rats and mice); >2000 mg/kg[3] (waterfowl) |
LC50 (median concentration) |
46 mg/L (fish)[2] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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American farmers used 405,000 pounds (184 t) in 1974, though trifluralin still overshadowed it, with 22,960,000 pounds (10,410 t).[11] A 1992 report mentions extensive use on potatoes,[6] though Shell's "Planavin" trademark expired in 1989.[12]
On ryegrass meristems, nitralin suppressed elongation and made the roots wider. After 1 hour, mitosis was reduced by 76%. Cell nuclei expanded, becoming polymorphic, and with increased ploidy levels. Other dinitroanilines have similar effects, except butralin.[13]
Nitralin is not associated with lung cancer.[10]
Planavin
Planavin 75 was sold commercially as a wettable powder containing 75% nitralin, applied at around 2 pounds per acre (2.25 kg/Ha), equivalent to 1.5 lbs/acre of pure nitralin.[7] Shell sold technical grade nitralin at 94% purity for manufacturing purposes.[14]
Environmental Behaviour
Soil-applied nitralin is involatile; its vapours were below the limit of detection.[15] Water leaching is very slow. Together this makes nitralin immobile in soil, so application can be precise, though it cannot move far enough into soil to control deep-germinating weed species. Typical in-soil halflives are 30 to 60 days, and it decomposes under ultraviolet light.[16]
Metabolism
Ingested by rats, 98.5% is removed in 72 hours by urine and faeces. The metabolism is complex and produces many afterproducts.[17]
Comparative Performance
Compared to trifluralin, nitralin is more toxic to the roots and less toxic to the shoots. Trifluralin prevented emergence of most species tested; nitralin did not prevent any from emerging.[18] At Johnsongrass control, nitralin and pendimethalin lost out to trifluralin and other dinitroaniline herbicides.[19]
Nitralin in a 1970s trial on conifer seedbeds in Connecticut was effective at 2 lbs/ac (2.24 kg/Ha) though it damaged white spruce seedlings in one test. Of the related dinitroanilines, oryzalin was most active, and nitralin was not far off, beating trifluralin.[20]
Applications
| Broadleaves Controlled[7][21][22][17] | Grasses Controlled[7][21][22][17] | Crops used on | Turfs used on[7] |
|---|---|---|---|
| amsinckia, amaranth, buckhorn plantain, bull mallow, carpetweed, common plantain, cress, curly dock (from seed), dead nettle, fat hen, fiddleneck, groundsel, henbit, knotweed, lambsquarter, mallow of Nice, munyeroo, pigweed, plantain, prickly lettuce, price-of-wales feather, purslane, pussley, shepherd's purse, smartweed | Annual bluegrass, annual ryegrass, brachiaria, burr grass, cheatgrass, crabgrass, cotton panic grass, cupgrass, downy brome, finger panic grass, goosegrass, green foxtail, ryegrass, johnsongrass, pigeon grass, setaria, watergrass, wild oats, winter grass, wireweed, witchgrass, yellow foxtail | vines, soybeans, cotton, beans, groundnuts, sunflowers, tobacco,[8] turf[7] | bahia, bentcrass, bermuda grass, annual bluegrass, centipede, fescue, St. Augustine, zoysia, Japanese andromeda, Japanese holly, Azalea, boxwood, chrysanthemum, shasta daisy, ajuga |