Propachlor

Chemical Properties

Propachlor is a light tan solid.

Chemical Properties

Tan powder. Mp 68C. Soluble in alcohol, benzene.

Uses

Herbicide.

Uses

Selective preemergence herbicide used to control most annual grasses and some broad-leaved weeds in brassicas, corn, cotton, flax, leeks, maize, milo, onions, peas, roses, ornamental trees and shrubs, soybeans, sugarcane.

Definition

ChEBI: An anilide that consists of 2-chloroacetanilide bearing an N-isopropyl substituent.

General Description

Light tan solid. Corrosive to iron and steel. Used as an herbicide.

Air & Water Reactions

Hydrolyzed by strong acid and base.

Reactivity Profile

A chloroacetanilide derivative.

Hazard

Toxic by ingestion and skin absorption.

Agricultural Uses

Herbicide: 217-638-2 [Annex I Index No.: 616-008-00-8] Uses: A pre-emergence herbicide used to combat annual grasses and broad-leaved weeds in corn, sorghum, soybeans, cotton, sugar cane, sugar beets, vegetable crops, forage crops, pasture land and range land. Also used to control weeds in groundnuts, leeks, onions, peas, maize, roses and ornamental trees and shrubs. Not approved for use in EU countries. Not registered for use in the U.S. except California.

Trade name

AATRAM®[C]; ACLID®; AI3-51503®; ALBRASS®; BEXTON®[C]; CIPA®; CP 31393®; KARTEX A®; NITICID®; RAMROD®; RAMROD® 65; SATECID®; WALLOP®[C]

Potential Exposure

Those engaged in the manufacture, formulation and application of this preemergence herbicide which is used to combat annual grasses and broad-leaved weeds in corn, soybeans, cotton, sugar cane and vegetable crops.

Environmental Fate

Biological. In the presence of suspended natural populations from unpolluted aquatic systems, the second-order microbial transformation rate constant determined in the laboratory was reported to be 1.1 × 10–9 L/organisms-hour (Steen, 1991).
Groundwater. According to the U.S. EPA (1986) propachlor has a high potential to leach to groundwater.
Plant. In corn seedlings and excised leaves of corn, sorghum, sugarcane and barley, propachlor was metabolized to at least three water-soluble products. Two of these metabolites were identified as a γ-glutamylcysteine conjugate of propachlor and a glutathione conjugate of propachlor. It was postulated that both compounds were intermediate compounds in corn seedlings since they were not detected 3 days following treatment (Lamoureux et al., 1971).
Photolytic. When propachlor in an aqueous ethanolic solution was irradiated with UV light (λ = 290 nm) for 5 hours, 80% decomposed to the following cyclic photo-products: N-isopropyloxindole, N-isopropyl-3-hydroxyoxindole and a spiro compound. Irradiation of propachlor in an aqueous solution containing riboflavin as a sensitizer resulted in completed degradation of the parent compound. m-Hydroxypropachlor was the only compound identified in trace amounts which formed via ring hydroxylation (Rejt? et al., 1984). Hydrolyzes under alkaline conditions forming N-isopropylaniline (Sittig, 1985) which is also a product of microbial metabolism (Novick et al., 1986).
Chemical/Physical. Emits toxic fumes of nitrogen oxides and chlorine when heated to decomposition (Sax and Lewis, 1987). Hydrolyzes under alkaline conditions forming N-isopropylaniline (Sittig, 1985) which is also a product of microbial metabolism (Novicket al., 1986). Propachlor is rapidly hydrolyzed in Water (Yu et al., 1975a). The hydrolysis half-lives at 68.0°C and pH values of 3.10 and 10.20 were calculated to be 36.6 and 1.2 days, respectively (Ellington et al., 1986).

Shipping

UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN2588 Pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN3077 Environmentally hazardous sub- stances, solid, 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 explo- sions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Attacks carbon steel. 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 flam- mable gases), thiosulfates and dithionites (releasing hydrogen sulfate and oxides of sulfur).

Waste Disposal

Alkaline hydrolysis would yield N-isopropylaniline. However, incineration @ 850 ? C together with flue gas scrubbing is the preferred disposal method .