Metolachlor

Description

Metolachlor is a colorless or tan to brown,oily liquid with a slightly sweet odor. Molecularweight 5 283.83; Boiling point = 100℃ at 0.001 mmHg. Itis stable to about 300℃. Hazard Identification (based onNFPA-704 M Rating System): Health 1, Flammability 0,Reactivity 0. Slightly soluble in water.

Chemical properties

Pale Yellow Oil

Chemical properties

Metolachlor is a colorless or tan to brown, oily liquid. Slightly sweet odor.

The Uses of Metolachlor

A selective pre-emergence herbicide.

The Uses of Metolachlor

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.

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.

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Note to physician: Treat for methemoglobinemia.Spectrophotometry may be required for precise determination of levels of methemoglobin in urine.

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.

storage

Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with thischemical you should be trained on its proper handling andstorage. Store in tightly closed containers in a cool, wellventilated area away from oxidizers. Where possible, automatically pump liquid from drums or other storage containers to process containers

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.