Propanil

Description

propanil is used as a rice herbicide. The resistance of rice plants toward propanil has been found in an enzyme aryl-acylamidase that rapidly hydrolyzes the herbicide. This enzyme can be inhibited by carbamate insecticides, and this can lead to an increased propanil phytotoxicity (38).

Chemical properties

(Pure) Light-brown solid.

Chemical properties

Propanil is a colorless solid. The technical product is a brown crystalline solid.

The Uses of Propanil

Selective preemergence and postemergence herbicide used to control many grasses and broad-leaved weeds in potatoes, rice and wheat.

The Uses of Propanil

Postemergence herbicide, especially for rice culture; nematocide.

The Uses of Propanil

Propanil is a a widely used herbicide. Propanil is used mainly to control weed growth in rice fields.

Definition

ChEBI: Propanil is an anilide resulting from the formal condensation of the carboxy group of propanoic acid with the amino group of 3,4-dichloroaniline. It is a herbicide used for the treatment of numerous grasses and broad-leaved weeds in rice, potatoes, and wheat. It has a role as a herbicide. It is an anilide and a dichlorobenzene. It is functionally related to a 3,4-dichloroaniline.

General Description

Colorless to brown crystals. Non corrosive. Used as an herbicide.

Air & Water Reactions

Hydrolyzed by acid and alkaline media.

Reactivity Profile

Propanil is incompatible with carbamates and organophosphates.

Hazard

Toxic by ingestion and inhalation.

Agricultural Uses

Herbicide: Propanil is a post-emergence herbicide with no residual effect. It is used against numerous grasses and broadleaved weeds in rice, potatoes, and wheat. Mixing with carbamates or organophosphorus compounds is not recommended. It is also used on wheat in a mixture with MCPA. With carbaryl, it is used in citrus crops grown in sod culture. Not approved for use in EU countries (re-submitted). Registered for use in the U.S.

Trade name

Cekupropanil; DCPA; N-(3,4-Dichlorophenyl) propanamide; 3',4'-Dichlorophenyl propionanilide; 3,4-Dichloropropionanilide; 3',4'-Dichloropropionanilide; Dichloropropionanilide; Dipram; DPA; NSC 31312; Propanamide, N-(3,4-Dichlorophenyl)-; Propanide; Propionanilide, 3',4'-Dichloro-; Propionic acid, 3,4-dichloroanilide

Safety Profile

Poison by ingestion. Moderately toxic by an unspecified route. Mildly toxic by skin contact. Mutation data reported. When heated to decomposition it emits very toxic fumes of Cl and NOx.

Potential Exposure

Propanil is used as a postemergent herbicide for rice and spring wheat. A potential danger to those involved in the manufacture, formulation, and application of this contact herbicide.

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 5 × 10–10 L/organisms-hour (Steen, 1991).
Soil. Propanil degrades in soil forming 3,4-dichloroaniline (Bartha, 1968; Bartha and Pramer, 1970; Chisaka and Kearney, 1970; Bartha, 1971; Duke et al., 1991; Pothuluri et al., 1991) which is further degraded by microbial peroxidases to 3,3′,4,4′-tetrachloroazobenzene (Bartha and Pramer, 1967; Bartha et al., 1968; Chisaka and Kearney, 1970), 3,3′,4,4′-tetrachloroazooxybenzene (Bartha and Pramer, 1970), 4-(3,4-dichloroanilo)- 3,3′,4,4′-tetrachloroazobenzene (Linke and Bartha, 1970) and 1,3-bis(3,4-dichlorophenyl)triazine (Plimmer et al., 1970a), propanoic acid, carbon dioxide and unidentified products (Chisaka and Kearney, 1970). Evidence suggests that 3,3′,4,4′-tetrachloroazobenzene reacted with 3,4-dichloroaniline forming a new reaction product, namely 4-(3,4- dichloroanilo)-3,3′,4′-trichloroazobenzene (Chisaka and Kearney, 1970). Under aerobic conditions, propanil in a biologically active, organic-rich pond sediment underwent dechlorination at the para- position forming N-(3-chlorophenyl)propanamide (Stepp et al., 1985). Residual activity in soil is limited to approximately 3–4 months (Hartley and Kidd, 1987).
Plant. In rice plants, propanil is rapidly hydrolyzed via an aryl acylamidase enzyme isolated by Frear and Still (1968) forming the nonphototoxic compounds (Ashton and Monaco, 1991) 3,4-dichloroaniline, propionic acid (Matsunaka, 1969; Menn and Still, 1977; Hatzios, 1991) and a 3′,4′-dichloroaniline-lignin complex. This complex was identified as a metabolite of N-(3,4-dichlorophenyl)glucosylamine, a 3,4-dichloroaniline saccharide conjugate and a 3,4-dichloroaniline sugar derivative (Yi et al., 1968). In a rice field soil under anaerobic conditions, however, propanil underwent amide hydrolysis and dechlorination at the para position forming 3,4-dichloroaniline and m-chloroaniline (Pettigrew et al., 1985). In addition, propanil may degrade indirectly via an initial oxidation step resulting in the formation of 3,4-dichlorolacetanilide which is further hydrolyzed to 3,4-dichloroaniline and lactic acid (Hatzios, 1991). In an earlier study, four metabolites were identified in rice plants, two of which were positively identified as 3,4-dichloroaniline and N-(3,4-dichlorophenyl)glucosylamine (Still, 1968).
Photolytic. Photoproducts reported from the sunlight irradiation of propanil (200 mg/L) in distilled water were 3′-hydroxy-4′-chloropropionanilide, 3′-chloro-4′-hydroxypropionanilide, 3′,4′-dihydroxypropionanilide, 3′-chloropropionanilide, 4′-chloropropionanilide, propionanilide, 3,4-dichloroaniline, 3-chloroaniline, propionic acid, propionamide, 3,3′,4,4′-tetrachloroazobenzene and a dark polymeric humic substance. The photolysis products resulted from the reductive dechlorination, replacement of chlorine substituents by hydroxyl groups, formation of propionamide, hydrolysis of the amide group and azobenzene formation (Moilanen and Crosby, 1972). Tanaka et al. (1985) studied the photolysis of propanil (100 mg/L) in aqueous solution using UV light (λ = 300 nm) or sunlight. After 26 days of exposure to sunlight, propanil degraded forming a trichlorinated biphenyl product (<1% yield) and hydrogen chloride (Tanaka et al., 1985).
Chemical/Physical. Hydrolyzes in acidic and alkaline media to propionic acid (Worthing and Hance, 1991) and 3,4-dichloroaniline (Sittig, 1985; Worthing and Hance, 1991). The half-life of propanil in a 0.50 N sodium hydroxide solution at 20°C was determined to be 6.6 days (El-Dib and Aly, 1976).

Shipping

UN3077 Environmentally hazardous substances, 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.

Waste Disposal

Hydrolysis in acidic or basic media yields the more toxic substance, 3,4-dichloraniline, and is not recommended.