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| | Metolachlor Basic information |
| | Metolachlor Chemical Properties |
| Melting point | 25°C | | Boiling point | bp0.001 100° | | density | 1.1200 | | refractive index | 1.526-1.529 | | Fp | 2 °C | | storage temp. | APPROX 4°C
| | solubility | Chloroform (Slightly), DMSO (Slightly), Methanol (Slightly) | | pka | 1.45±0.50(Predicted) | | form | neat | | Odor | wh. to tan clear liq., odorless | | Water Solubility | 529.7mg/L(20 ºC) | | BRN | 8396147 | | CAS DataBase Reference | 51218-45-2(CAS DataBase Reference) | | NIST Chemistry Reference | Metolachlor(51218-45-2) | | EPA Substance Registry System | Metolachlor (51218-45-2) |
| | Metolachlor Usage And Synthesis |
| Chemical Properties | Pale Yellow Oil | | Chemical Properties | Metolachlor is a colorless or tan to brown, oily
liquid. Slightly sweet odor. | | Uses | Preemergence herbicide used to control most annual grasses and many annual weeds
in beans, chickpeas, corn, cotton, milo, okra, peanuts, peas, potatoes, safflower, soybeans
and some ornamentals. | | Uses | A selective pre-emergence herbicide. | | Definition | ChEBI: 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(1-methoxypropan-2-yl)acetamide is an organochlorine compound that is 2-chloroacetamide substituted by a (2-ethyl-6-methylphenyl)-N-(1-methoxypropan-2-yl) group at the nitrogen atom. It is an aromatic amide, an ether, a member of benzenes and an organochlorine compound. | | General Description | Tan to brown oily liquid with a slightly sweet odor. Slightly soluble in water and denser than water. Hence sinks in water. Soluble in most organic solvents. Used as a selective herbicide. | | Air & Water Reactions | Slightly soluble in water. Hydrolyzed by strong mineral acids and strong alkalis. | | Reactivity Profile | Metolachlor is a chlorinated acetamide. May react with azo and diazo compounds to generate toxic gases. May form flammable gases with strong reducing agents. Combustion generates mixed oxides of nitrogen (NOx). | | Health Hazard | Can cause skin irritation and eye irritation. Headache and nausea may occur following prolong exposure. | | Agricultural Uses | Herbicide: Not approved for use in EU countries. Registered
for use in the U.S. Metolachlor is a selective herbicide that
is usually applied to crops before plants emerge from the
soil, and is used to control certain broadleaf and annual
grassy weeds in field corn, soybeans, peanuts, grain sorghum,
potatoes, pod crops, cotton, safflower, stone fruits,
nut trees, highway rights-of-way and woody ornamentals.
Prior to the RED of April, 1995, its primary use was on
corn, soybeans and sorghum. It inhibits protein synthesis;
thus, high-protein crops (e. g., soy) can be adversely
affected by excessive metolachlor application. Additives
may be included in product formulations to help protect
sensitive crops (i.e., sorghum) from injury. | | Trade name | BICEP®[C]; BROADSTRIKE®; CGA-
24705®; CINCH®; CODAL®; COTORAN® MULTI®;
CYCLE®[C] DREXEL ME-TOO-LACHLOR®; DUAL®;
DUAL MAGNUM®; DUET®[C]; INTER PLUS®;
MEDAL®[C]; MILOCEP®; ONTRACK 8E®[C];
PENNANT®[C]; PRELUDE®[C]; PRIMAGRAM®;
PRIMEXTRA®; TURBO® | | Potential Exposure | Metolachlor is a chlorinated acetamide
selective herbicide used for weed control in corn and for
controlling grasses in a variety of crops including cotton
and peanuts. | | Environmental Fate | Soil. Metolachlor and its degradation products combine with humic acids in soils and
small quantities are degraded to carbon dioxide (Ashton and Monaco, 1991). In soil, the
fungus Chaetomium globosum degraded metolachlor to 2-chloro-N-(2-ethyl-6-methylphenyl)
acetamide, 2-hydroxy-N-(2-methylvinylphenyl)-N-(methoxyprop-2-yl)acetamide, 3-
hydroxy-8-methyl-N-(methoxyprop-2-yl)-2-oxo-1,2,3,4-tetrahydraquinoline, 2-chloro-N-
(2-ethyl-6-methylphenyl)-N-(hydroxyprop-2-yl)acetamide and the tentatively identified
compounds 3-hydroxy-1-isopropyl-8-methyl-2-oxo-1,2,3,4-tetrahydroquinoline, N-(methoxyprop-
2-yl)-8-methyl-2-oxo-1,2,3,4-tetrahydroquinoline, N-(methoxyprop-2-yl)-N-(2-
methyl-6-vinyl)aniline and 1-(methoxyprop-2-yl)-7-methyl-2,3-dihydroindole (McGahen
8). Metolachlor was transformed by a strain of soil actinomycetes to the following products:
2-chloro-N-(2-ethyl-6-methylphenyl)-N-(hydroxyprop-2-yl)acetamide, 2-chloro-N-
2-(1-hydroxyethyl)-6-(methylphenyl)-N-(hydroxyprop-2-yl)acetamide, 2-chloro-N-(2-
ethyl-6-hydroxymethylphenyl)-N-(hydroxy-prop-2-yl)-acetamide, diastereoisomers of 2-
chloro-N-(2-ethyl-6-hydroxymethylphenyl)-N-(methoxyprop-2-yl)acetamide and 2-
chloro-N-2-(hydroxyethyl)-6-hydroxymethylphenyl)-N-(methoxyprop-2-yl)acetamide.
These products were formed via hydroxylation of both the N-alkyl and alkyl side chains
(Krause et al., 1985). In sterilized soil, metolachlor did not degrade after 4 months
(Bouchard et al., 1982).
Zimdahl and Clark (1982) reported half-lives of 15–38 and 33–100 days for the
herbicide in clay loam soil and sandy loam soil, respectively. They also reported that soil
moisture increased the dissipation rate. At 20°C, the dissipation rates of metolachlor in
the clay loam and sandy loam soils at 20, 50 and 80% soil moisture contents were 0.028,
0.053, 0.062 and 0.016, 0.028 and 0.037/day, respectively. The half-lives of metolachlor
in soil at maintained at temperatures of 30 and 40°C were approximately 3.85 and 2.75
weeks, respectively (Bravermann et al., 1986). The reported half-lives of metolachlor in
soil is approximately 6 days (Worthing and Hance, 1991) and 3–4 weeks (Bowman, 1988).
Groundwater. According to the U.S. EPA (1986) metolachlor has a high potential to
leach to groundwater.
Plant. Metabolizes in plants forming water soluble, polar, nonvolatile products (Hartley
and Kidd, 1987) and glutathione conjugates (Breaux et al., 1987).
Chemical/Physical. The volatilization half-life of metolachlor in an unstirred solution
was 20 days at 40°C. Volatilization is not significant at temperatures < 25°C (Lau et al.,
1995). | | Metabolic pathway | A stable bacterial community absorbs and transforms
metolachlor from a liquid medium. From the medium
of the 7 day-old culture of the bacterial community, 2-
hydroxy-N-(2-methyl-6-vinylphenyl)-N-(2-methoxy-
methylethyl)acetamide and 4-(2-ethyl-6-methylphenyl)-
5-methyl-3-morpholinone are identified. The products
recovered from cells of J4-A include dechlorinated
metolachlor, a thiol compound, a more complicated
conjugate, and a non-sulfur-containing conjugate. By
sorghum microsomes, O-demethylation occurs in the
metolachlor degradation process. | | Shipping | UN2902 Pesticides, liquid, toxic, n.o.s., Hazard
Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name
Required. UN3082 Environmentally hazardous substances,
liquid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous
hazardous material, Technical Name Required. | | Incompatibilities | Incompatible with oxidizers (chlorates,
nitrates, peroxides, permanganates, perchlorates, chlorine,
bromine, fluorine, etc.); contact may cause fires or explosions.
Keep away from alkaline materials, strong bases,
strong acids, oxoacids, epoxides, nitrates. Compounds of
the carboxyl group react with all bases, both inorganic and
organic (i.e., amines) releasing substantial heat, water and a
salt that may be harmful. Incompatible with arsenic compounds
(releases hydrogen cyanide gas), diazo compounds,
dithiocarbamates, isocyanates, mercaptans, nitrides, and
sulfides (releasing heat, toxic, and possibly flammable
gases), thiosulfates and dithionites (releasing hydrogen
sulfate and oxides of sulfur). | | Waste Disposal | In accordance with 40CFR
165 recommendations for the disposal of pesticides and
pesticide containers. Must be disposed properly by following
package label directions or by contacting your local or
federal environmental control agency, or by contacting
your regional EPA office. |
| | Metolachlor Preparation Products And Raw materials |
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