Trifluralin

Description

Trifuralin (sold under trademe such as Treflan, Elancolan or Trefanocide) is a selective pre-emergence herbicide. It is used for pre-plant soil incorporation for the control against annual grasses and some broadleaf annual weeds. It is widely used on soybeans and cotton. It also finds its use in a large number of food crops, including broccoli, cabbage, onions, leafy green vegetables, beans, tomatoes, potatoes, wheat, sugar beet, and sugar cane. For its use on fruit trees, the plant must not be bearing fruit at the time of application. It may also be used to protect residential ornamental plants, such as trees, herbaceous plants, woody shrubs, and vines.
Trifluralin has low water solubility. It has high affinity for soil and is relatively immobile. It is not acutely toxic mammals, but it is highly toxic to fish and other aquatic organisms.

References

1. https://www.epa.gov
2. http://www.toxipedia.org
3. https://pubchem.ncbi.nlm.nih.gov
4. http://www.who.int
5. https://aggie-horticulture.tamu.edu

Description

Trifluralin is a dinitroaniline herbicide that is approved for preemergence use to control broadleaf weeds in a variety of crops and plants. First approved nearly 50 years ago, trifluralin is a common commercially available herbicide which is used extensively in the United States and other countries. In the early 2000s, trifluralin was banned in Europe following reports of persistence in soil and groundwater leading to concerns of increased risk for toxicity. In general, trifluralin is viewed as a safe herbicide when used according to the instructions. Minimal to no toxicity has been reported in humans following either oral, dermal, or inhalation exposure. There is some evidence that once trifluralin enters the soil and groundwater, it undergoes a complex and extensive series of metabolic steps and can exist as multiple intermediaries depending on the extent of the degradation. This has led to findings that trifluralin may have elevated toxicity in certain aquatic wildlife as particular species of fish and tadpoles have displayed biomarkers of trifluralin toxicity following exposure. Larger vertebrates such as canines have also demonstrated toxicological profiles suggesting an elevated toxicity compared to humans.

Chemical Properties

Yellowish-orange solid. Insoluble in water; soluble in xylene, acetone, and ethanol.

Chemical Properties

Trifluralin is an orange crystalline solid.

Uses

Preemergence herbicide for controlling many grasses and broad-leaved weeds.

Uses

Pre-emergence herbicide used for grass control in crops.

Uses

Trifluralin is a herbicide, first approved in 1963, for control of annual grasses and broadleaf weeds on a variety of crops. Trifluralin is registered for nonfood uses including residential use. Trifluralin comes in a variety of formulations and is applied as a soil-incorporated treatment.

Production Methods

The production of trifluralin, a widely used pre-emergent herbicide, involves a multi-step chemical synthesis starting from 4-chlorotrifluoromethylbenzene. This compound undergoes a two-stage nitration process to form 2,6-dinitro-4-trifluoromethylchlorobenzene. The nitrated intermediate is then reacted with di-N-propylamine, which replaces the chlorine atom to yield trifluralin—2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)aniline. Ethylene dichloride is typically used as a solvent, and spent acids from the nitration steps are recycled to improve efficiency.

Definition

ChEBI: A substituted aniline that is N,N-dipropylaniline substituted by a nitro groups at positions 2 and 6 and a trifluoromethyl group at position 4. It is an agrochemical used as a pre-emergence herbicide.

General Description

Yellow-orange crystalline solid. Denser than water and not soluble in water. Hence sinks in water. Melting point 48.5-49°C. Used as a selective pre emergence herbicide.

Reactivity Profile

Trifluralin is a trifluoromethyl dinitroaniline derivative. Dinitroaniline has a record of industrial explosions. Nothing has been reported implicating Trifluralin in any such accidents. This may be because of the trifluoromethyl substitution may mitigate the instability of the molecule. However, care should be taken in the extremes of heat, shock, and friction sources that may trigger an explosive release of energy.

Health Hazard

Dust may irritate eyes. No toxic symptoms have been observed during the manufacture and use of Trifluralin.

Fire Hazard

Special Hazards of Combustion Products: Toxic and irritating hydrogen fluoride gas may be formed in fires.

Agricultural Uses

Herbicide: Trifluralin is a selective, pre-emergence herbicide used to control many annual grasses and broadleaf weeds in a large variety of tree fruit, nut, vegetable, and grain crops, including soybeans, sunflowers, cotton, and alfalfa. It is also used on rights-of-way, on set-aside land (i.e., arable land temporarily taken out of use). A general use pesticide (GUP). Not approved for use in EU countries . Registered for use in the U.S.

Trade name

AGREFLAN®; AGRIFLAN® 24; ASHLADE TRIMARAN®; AUTUMN KITE®; BROADSTRIKE®; BUCKLE®; CALLIFORT®; CAMPBELL'S TRIFLURON®; CHANDOR®; COMMENCE®; CRISALIN®; DEVRINOL T®; DIGERMIN®; ELANCOLAN®; FLINT®; FLORA®; FLURENE SE®; FLUTRIX®; FREEDOM®; GORDON’S WEEDER®; HERBIFLURIN®; IPERSAN®; JANUS®; L-36352®; LILLY 36,352®; LINNET®; MARKSMAN®; MARKSMAN 2, TRIGARD®; M. T. F®; NITRAN®; OLITREF®; ONSLAUGHT®; PREMERLIN 600 CE®; SINFLOWAN®; SOLO®; SU SEGURO CARPIDOR®; TEAM®; TREFANOCIDE®; TREFICON®; TREFLAN®; TREFLANOCIDE®; TRIFARMON®; TRIFLURALINA® 600; TRIFLUREX®; TRIFUREX®; TRIGARD®; TRIKEPIN®; TRILIN®; TRILIN® 10G; TRIM®; TRIMARAN®; TRIPART TRIFLURALIN 48 EC; TRISTAR®; TRUST®; TURFLAN®; URANUS® (trifluralin + linuron)

Mechanism of action

Selective. Inhibition of mitosis and cell division. Microtubule assembly inhibition.

Safety Profile

Moderately toxic by ingestion and intraperitoneal routes. Experimental teratogenic and reproductive effects. Questionable carcinogen with experimental carcinogenic and tumorigenic data. Human mutation data reported. When heated to decomposition it emits very toxic fumes of Fand NOx. See also FLUORIDES.

Potential Exposure

A potential danger to those involved in the manufacture, formulation and application of this selective, preemergence herbicide.

Environmental Fate

Biological. Laanio et al. (1973) incubated 14CF3-triuralin with Paecilomyces, Fusar- ium oxysporum, or Aspergillus fumigatus and reported that <1% was converted to 14CO2. From the first-order biotic and abiotic rate constants of triuralin in estuarine water and sediment/water systems, the estimated biodegradation half-lives were 2.5–9.7 and 2.4–7.1 days, respectively (Walker et al., 1988).
Soil. Anaerobic degradation in a Crowley silt loam yielded α,α,α-triuoro-N4,N4- dipropyl-5-nitrotoluene-3,4-diamine and α,α,α-triuoro-N4,N4-dipropyltoluene-3,4,5-tri- amine (Parr and Smith, 1973). Probst and Tepe (1969) reported that triur
Golab et al. (1979) studied the degradation of triuralin in soil over a 3-year period. They found that the herbicide undergoes N-dealkylation, reduction of nitro substituents, followed by the formation cyclized products. Of the 28 transformation products
Zayed et al. (1983) studied the degradation of triuralin by the microbes Aspergillus carneus, Fusarium oxysporum and Trichoderma viride. Following an inoculation and incubation period of 10 days in the dark at 25°C, the following metabolites were identified: α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine, α,α,α-trifluoro-2,6-dinitro-p-toluidine, 2-amino-6-nitro-α,α,α-triuoro-p-toluidine and 2,6-dinitro-4-triuoromethyl phenol. The reported half-life in soil is 132 days (Jury et al., 1987).
The half-lives for triuralin in soil incubated in the laboratory under aerobic and anaerobic conditions ranged from 33 to 375 days (Probst et al., 1967; Parr and Smith, 1973; Kearney et al., 1976; Zimdahl and Gwynn, 1977) to 4 to 70 days, respectively (

Solubility in organics

Freely soluble in Stoddard solvent (Windholz et al., 1983), chloroform, methanol (Probst et al., 1967), acetone (400 g/L), xylene (580 g/L) (Worthing and Hance, 1991), ether, and ethanol (quoted, Bailey and White, 1965)

Shipping

UN2588 Pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required.

Toxicity evaluation

Technical trifluralin has low acute toxicity, whereas solvents often used for the emulsification of trifluralin have been shown to be irritating to the eyes and skin. An active component of trifluralin toxicity is the volatile nitrosamine, N-nitroso-din- propylamine, which may be the active compound in trifluralin toxicity.

Incompatibilities

Trifluralin is a trifluoromethyl dinitroaniline derivative. Dinitroaniline has a record of industrial explosions. Nothing has been reported implicating trifluralin in any such accidents. This may be because of the trifluoromethyl substitution may mitigate the instability of the molecule. However, care should be taken in the extremes of heat, shock, and friction sources that may trigger an explosive release of energy. Fluorocarbons can react violently with barium, potassium, sodium.

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed. Trifluralin does contain fluorine, and therefore incineration presents the increased hazard of HF in the off-gases. Prior to incineration, fluorine-containing compounds should be mixed with slaked lime plus vermiculite, sodium carbonate or sand-soda ash mixture (90-10).

Pesticide Type

Herbicide