Alachlor

Last updated
Alachlor
Alachlor.png
Alachlor-3D-spacefill.png
Names
Preferred IUPAC name
2-Chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.036.448 OOjs UI icon edit-ltr-progressive.svg
KEGG
PubChem CID
RTECS number
  • AE1225000
UNII
  • InChI=1S/C14H20ClNO2/c1-4-11-7-6-8-12(5-2)14(11)16(10-18-3)13(17)9-15/h6-8H,4-5,9-10H2,1-3H3 Yes check.svgY
    Key: XCSGPAVHZFQHGE-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C14H20ClNO2/c1-4-11-7-6-8-12(5-2)14(11)16(10-18-3)13(17)9-15/h6-8H,4-5,9-10H2,1-3H3
    Key: XCSGPAVHZFQHGE-UHFFFAOYAO
  • ClCC(=O)N(c1c(cccc1CC)CC)COC
  • CCc1cccc(c1N(COC)C(=O)CCl)CC
Properties
C14H20ClNO2
Molar mass 269.767 g/mol
Appearancecream-coloured solid
Odor odorless
Density 1.133 g/cm3
Melting point 39.5 °C (103.1 °F; 312.6 K)
Boiling point 404 °C (759 °F; 677 K)
0.0242 g/100 mL
Solubility soluble in acetone, benzene, chloroform, ethanol, ethyl ether, ethyl acetate
Vapor pressure 1x106 mmHg
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Toxic
Flash point 198 °C (388 °F; 471 K)
Lethal dose or concentration (LD, LC):
930 mg/kg
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)
A person mixing Lasso - A brand of alachlor made by Monsanto Monsanto's Lasso herbicide (cropped).jpg
A person mixing Lasso - A brand of alachlor made by Monsanto

Alachlor is an herbicide from the chloroacetanilide family. It is an odorless, white solid. The greatest use of alachlor is for control of annual grasses and broadleaf weeds in crops. Use of alachlor is illegal in the European Union [1] and no products containing alachlor are currently registered in the United States. [2]

Contents

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. [3]

Uses

The largest use of alachlor is as a herbicide for control of annual grasses and broadleaf weeds in crops, primarily on corn, sorghum, and soybeans. [4]

Application details

Alachlor mixes well with other herbicides. It is marketed in mixed formulations with atrazine, glyphosate, trifluralin and imazaquin. It is a selective, systemic herbicide, absorbed by germinating shoots and by roots. Its mode of action is elongase inhibition, and inhibition of geranylgeranyl pyrophosphate (GGPP) cyclisation enzymes, part of the gibberellin pathway. [3] Stated more simply, it works by interfering with a plant's ability to produce protein and by interfering with root growth. [5] [6]

It is most commonly available as microgranules containing 15% active ingredients (AI), or emulsifiable concentrate containing 480 g/ litre of AI. Homologuation in Europe requires a maximum dose of 2,400 g per hectare of AI, 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. [7]

Safety

The United States Environmental Protection Agency (EPA) classifies the herbicide as toxicity class III - slightly toxic. [6] The Maximum Contaminant Level Goal (MCLG) for Alachlor is zero, to prevent long-term effects. The Maximum Contaminant Level (MCL) for drinking water is two parts per billion (2 ppb). [8]

The EPA cited the following long-term effects for exposures at levels above the MCL in drinking water exposed to runoff from herbicide used on row crops: 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. The major source of environmental release of alachlor is through its manufacture and use as a herbicide. Alachlor was detected in rural domestic well water by EPA's National Survey of Pesticides in Drinking Water Wells. EPA's Pesticides in Ground Water Database reports detections of alachlor in ground water at concentrations above the MCL in at least 15 U.S. states. [9]

Alachlor is a controlled substance under Australian law and is listed as a Schedule 7 (Dangerous Poison) substance. Access, use and storage are strictly controlled under state and territory law. [10] Since 2006, use of alachlor as a herbicide has been banned in the European Union. [1]

In "a judgment that could lend weight to other health claims against pesticides," in January, 2012 a French court found Monsanto, which manufactures Lasso, liable for chemical poisoning of a French farmer in 2004. [11] In 2015 a French appeals court upheld the ruling and ordered the company to "fully compensate" the grower. [12]

Environmental fate

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 multiple metabolites. The half life in aerobic soil ranges from about 6 to 15 days and is considerably shorter under anaerobic conditions. [13] 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. [14] Similar observations have been reported for the herbicides trifluralin and atrazine.

Alachlor is often used in high school chemistry classrooms as a reactant in demonstrations such as the combustion of magnesium. Alachlor can be used as a substitution for methane gas in such an experiment when gas is not available. [15]

See also

Related Research Articles

<span class="mw-page-title-main">Herbicide</span> Chemical used to kill unwanted plants

Herbicides, also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds. Selective herbicides control specific weed species, while leaving the desired crop relatively unharmed, while non-selective herbicides can be used to clear waste ground, industrial and construction sites, railways and railway embankments as they kill all plant material with which they come into contact. Apart from selective/non-selective, other important distinctions include persistence, means of uptake, and mechanism of action. Historically, products such as common salt and other metal salts were used as herbicides, however these have gradually fallen out of favor and in some countries a number of these are banned due to their persistence in soil, and toxicity and groundwater contamination concerns. Herbicides have also been used in warfare and conflict.

Roundup is the brand name of a systemic, broad-spectrum glyphosate-based herbicide originally produced by Monsanto, which Bayer acquired in 2018. Glyphosate is the most widely used herbicide in the United States. As of 2009, sales of Roundup herbicides still represented about 10 percent of Monsanto's revenue despite competition from Chinese producers of other glyphosate-based herbicides. The overall Roundup line of products, which includes genetically modified seeds, represented about half of Monsanto's yearly revenue. The product is marketed to consumers by Scotts Miracle-Gro Company.

<span class="mw-page-title-main">Glyphosate</span> Broad-spectrum systemic herbicide and crop desiccant

Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase. It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. Its herbicidal effectiveness was discovered by Monsanto chemist John E. Franz in 1970. Monsanto brought it to market for agricultural use in 1974 under the trade name Roundup. Monsanto's last commercially relevant United States patent expired in 2000.

<span class="mw-page-title-main">Dicofol</span> Chemical compound

Dicofol is an organochlorine pesticide that is chemically related to DDT. Dicofol is a miticide that is very effective against spider mite.

<span class="mw-page-title-main">Chlorfenvinphos</span> Chemical compound

Chlorfenvinphos is the common name of an organophosphorus compound that was widely used as an insecticide and an acaricide. The molecule itself can be described as an enol ester derived from dichloroacetophenone and diethylphosphonic acid. Chlorfenvinphos has been included in many products since its first use in 1963. However, because of its toxic effect as a cholinesterase inhibitor it has been banned in several countries, including the United States and the European Union. Its use in the United States was cancelled in 1991.

<span class="mw-page-title-main">Atrazine</span> Herbicide

Atrazine is a herbicide of the triazine class. It is used to prevent pre-emergence broadleaf weeds in crops such as maize (corn) and sugarcane and on turf, such as golf courses and residential lawns. Atrazine's primary manufacturer is Syngenta and it is one of the most widely used herbicides in the United States and Australian agriculture.

<span class="mw-page-title-main">Benomyl</span> Chemical compound

Benomyl is a fungicide introduced in 1968 by DuPont. It is a systemic benzimidazole fungicide that is selectively toxic to microorganisms and invertebrates, especially earthworms, but nontoxic toward mammals.

Chloropicrin, also known as PS and nitrochloroform, is a chemical compound currently used as a broad-spectrum antimicrobial, fungicide, herbicide, insecticide, and nematicide. It was used as a poison gas in World War I. Its chemical structural formula is Cl3CNO2.

<span class="mw-page-title-main">Fenthion</span> Chemical compound

Fenthion is an organothiophosphate insecticide, avicide, and acaricide. Like most other organophosphates, its mode of action is via cholinesterase inhibition. Due to its relatively low toxicity towards humans and mammals, fenthion is listed as moderately toxic compound in U.S. Environmental Protection Agency and World Health Organization toxicity class.

<span class="mw-page-title-main">Acetochlor</span> Chemical compound

Acetochlor is an herbicide developed by Monsanto Company and Zeneca. It is a member of the class of herbicides known as chloroacetanilides. Its mode of action is elongase inhibition, and inhibition of geranylgeranyl pyrophosphate (GGPP) cyclization enzymes, part of the gibberellin pathway. It carries high risks of environmental contamination.

<span class="mw-page-title-main">Dicamba</span> Chemical compound used as herbicide

Dicamba is a broad-spectrum herbicide first registered in 1967. Brand names for formulations of this herbicide include Dianat, Banvel, Diablo, Oracle and Vanquish. This chemical compound is a chlorinated derivative of o-anisic acid.

<span class="mw-page-title-main">Metolachlor</span> Chemical compound

Metolachlor is an organic compound that is widely used as an herbicide. It is a derivative of aniline and is a member of the chloroacetanilide family of herbicides. It is highly effective toward grasses.

<span class="mw-page-title-main">Pesticide drift</span> Diffusion of pesticides into the environment

Pesticide drift refers to the unintentional diffusion of pesticides and the potential negative effects of pesticide application, including off-target contamination due to spray drift as well as runoff from plants or soil. This can lead to damage in human health, environmental contamination, and property damage.

Pesticides in the United States are used predominantly by the agricultural sector, but approximately a quarter of them are used in houses, yards, parks, golf courses, and swimming pools.

<span class="mw-page-title-main">Trifluralin</span> Chemical compound

Trifluralin is a commonly used pre-emergence herbicide. With about 14 million pounds (6,400 t) used in the United States in 2001, it is one of the most widely used herbicides. Trifluralin is generally applied to the soil to provide control of a variety of annual grass and broadleaf weed species. It inhibits root development by interrupting mitosis, and thus can control weeds as they germinate.

<span class="mw-page-title-main">Bensulide</span> Chemical compound

Bensulide is a selective organophosphate herbicide. It is one of a few organophosphate compounds that are used as an herbicide. Most of the others are used as insecticides. It is used on vegetable crops such as carrots, cucumbers, peppers, and melons and in cotton and turfgrass to control annual grasses such as bluegrass and crabgrass and broadleaf weeds. It is often applied before the weed seeds germinate (pre-emergence) in order to prevent them from germinating. It is available as granules or an emulsifiable concentrate. Estimates place the total use of bensulide in the United States at about 632,000 pounds annually. Application rates may be relatively heavy when it is used. The EPA classifies bensulide as a general use pesticide.

This is an index of articles relating to pesticides.

<span class="mw-page-title-main">Imazaquin</span> Chemical compound

Imazaquin is an imidazolinone herbicide, so named because it contains an imidazolinone core. This organic compound is used to control a broad spectrum of weed species. It is a colorless or white solid, although commercial samples can appear brown or tan.

<span class="mw-page-title-main">Bentazon</span> Chemical compound

Bentazon is a chemical manufactured by BASF Chemicals for use in herbicides. It is categorized under the thiadiazine group of chemicals. Sodium bentazon is available commercially and appears slightly brown in colour.

<span class="mw-page-title-main">Cyanazine</span> Chemical compound

Cyanazine is a herbicide that belongs to the group of triazines. Cyanazine inhibits photosynthesis and is therefore used as a herbicide.

References

  1. 1 2 Thomas D. Boyer; Michael Peter Manns; Arun J. Sanyal; David Zakim (1990). Zakim and Boyer's Hepatology: A Textbook of Liver Disease. Saunders, 1990. p. 486. ISBN   1437708811 . Retrieved 4 September 2015.
  2. ↑ "Chemical Name". iaspub.epa.gov. Retrieved 2018-12-01.
  3. 1 2 Arnold P. Appleby, Franz Müller, Serge Carpy “Weed Control“ in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi : 10.1002/14356007.a28_165
  4. ↑ Shanmugasundaram, S.; Yeh, C.C.; Hartman, G.L.; Talekar, N.S. (1991). Vegetable Soybean Research Needs for Production and Quality Improvement (PDF). Taipei: Asian Vegetable Research and Development Center. p. 89. ISBN   9789290580478 . Retrieved 6 February 2016.
  5. ↑ Cornell Herbicide Profile
  6. 1 2 "EXTOXNET PIP - ALACHLOR". orst.edu. Retrieved 17 May 2015.
  7. ↑ "e-phy". Ministère de l'agriculture, de l'agroalimentaire (in French). Retrieved 30 April 2013.
  8. ↑ US EPA Consumer Factsheet
  9. ↑ "Consumer Factsheet on: ALACHLOR" (PDF). National Primary Drinking Water Regulations. United States Environmental Protection Agency (EPA. Retrieved 4 September 2015.
  10. ↑ "Poisons Standard 2013". comlaw.gov.au. Retrieved 17 May 2015.
  11. ↑ Douet, Marion (13 February 2012). "Monsanto guilty of chemical poisoning in France". Reuters. Retrieved 30 April 2013.
  12. ↑ "French court confirms Monsanto liable in chemical poisoning case". Reuters. 2015-09-11. Retrieved 2015-09-15.
  13. ↑ Vencill, W.K. 2002. WSSA herbicide handbook (8th edition). Weed Science Society of America. Lawrence, KS, USA. ISBN   1-891276-33-6.
  14. ↑ Xu, J., J. W. Stucki, J. Wu, J. Kostka, and G. K. Sims. 2001. Fate of atrazine and alachlor in redox-treated ferruginous smectite. Environmental Toxicology & Chemistry 20: 2717-2724.
  15. ↑ Kappa, Bromide 2013. Substitutions for methane gas in high school combustion demonstrations.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.