Propanil (3,4-dichloropropionanilide) is an acetanilide post-emergency herbicide with no residual effect. It can be prepared by reaction of 3,4-dichloroaniline with propionic acid in the presence of thionyl chloride. Propanil is in toxicity class II - moderately toxic, due to its potential to irritate eyes and skin.
Propanil functionalizes by the inhibition of RNA/protein synthesis and the inhibition of anthocyanin. Propanil is used to against numerous grasses and broad-leaved weeds in rice (mainly), potatoes, and wheat. It is typically applied aerially.
[1] S. M. Richards, G. Y. H. McClure, T. L. Lavy, J. D. Mattice, R. J. Keller, J. Gandy (2001) Propanil (3,4-Dichloropropionanilide) Particulate Concentrations Within and Near the Residences of Families Living Adjacent to Aerially Sprayed Rice Fields, Arch. Environ. Contam. Toxicol. 41, 112–116
[2] Michael A. Kamrin (1997) Pesticide Profiles: Toxicity, Environmental Impact, and Fate
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).
Propanil is a colorless solid. The technical
product is a brown crystalline solid.
(Pure) Light-brown solid.
Propanil is a a widely used herbicide. Propanil is used mainly to control weed growth in rice fields.
Selective preemergence and postemergence herbicide used to control many grasses
and broad-leaved weeds in potatoes, rice and wheat.
Postemergence herbicide, especially for rice
culture; nematocide.
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.
Colorless to brown crystals. Non corrosive. Used as an herbicide.
Hydrolyzed by acid and alkaline media.
Propanil is incompatible with carbamates and organophosphates.
Toxic by ingestion and inhalation.
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.
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
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.
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.
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).
UN3077 Environmentally hazardous substances,
solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous
hazardous material, Technical Name Required.
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.
Hydrolysis in acidic or basic
media yields the more toxic substance, 3,4-dichloraniline,
and is not recommended.
