| Alachlor | |
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2-Chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide |
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| Identifiers | |
| CAS number | 15972-60-8 |
| PubChem | 2078 |
| ChemSpider | 1994 |
| UNII | 24S2S61PXL |
| KEGG | C10928 |
| ChEBI | CHEBI:2533 |
| Jmol-3D images | Image 1 Image 2 |
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| Properties | |
| Molecular formula | C14H20ClNO2 |
| Molar mass | 269.767 g/mol |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Alachlor is an herbicide from the chloroacetanilide family. Its mode of action is elongase inhibition, and inhibition of geranylgeranyl pyrophosphate (GGPP) cyclisation enzymes, part of the gibberellin pathway. It is marketed under the trade names Alanex, Bronco, Cannon, Crop Star, Intrro, Lariat, Lasso, Micro-Tech, and Partner.[1]
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It is used to control the growth of broad-leafed weeds and grasses in corn and many other crops.
It mixes well with other herbicides, and is found in mixed formulations with atrazine, glyphosate, trifluralin, and imazaquin. It is used mainly to control annual grasses and broadleaf weeds in corn (maize), soybeans, and peanuts.[2][3]
It is most commonly available as microgranules containing 15% a.i., or emulsifiable concentrate containing 480 g/ litre of a.i. Homologuation in Europe requires a maximum dose of 2,400 g per hectare of a.i., or 5 litres/hectare of emulsifiable concentrate or 17 kg/ha of microgranules. The products are applied as either pre-drilling, soil incorporated, or pre-emergence.[4]
The United States Environmental Protection Agency classifies the herbicide as toxicity class III - slightly toxic.[5] The EPA has described the following effects when exposed to levels above the maximum contaminant level (MCL): slight skin and eye irritation; at lifetime exposure to levels above the MCL: potential damage to liver, kidney, spleen; lining of nose and eyelids; cancer.[6] Since 2006, use of alachlor as a herbicide is banned in the European Union
Alachlor exhibits moderate sorption in soil, ranging from 43-209 mL/g. Photodegradation is a minor contributor to alachlor fate. Degradation in soil appears to be largely biologically mediated, and produces a number of metabolites. The half life in aerobic soil ranges from about 6 to 15 days, and is considerably shorter under anaerobic conditions.[7] One possible explanation for the short anaerobic half life is the observation that alachlor is rapidly transformed under anoxia to up to 14 degradation products in the presence of iron-bearing ferruginous smectites. The iron in such minerals can be used by certain soil bacteria as an electron acceptor when soils are flooded, thus the process of herbicide transformation by reduced clay is thought to be microbially mediated.[8] Similar observations have been reported for the herbicides trifluralin and atrazine.
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