Prometryn

Description

Prometryn can be used in Pre- and postemergence to Control Annual grasses, broadleaf weeds.

Chemical Properties

Colorless crystalline solid.

Uses

Selective herbicide used to control many annual grasses and broad-leaved weeds in cotton, celery and peas.

Uses

Herbicide.

Uses

Prometryn is a methylthiotriazine herbicide used for the control of several annual grasses and broadleaf weeds. Prometryn works by inhibiting the electron transport in target broadleaves and grasses.

Production Methods

Prometryne is made either by reacting propazine with methyl mercaptan in the presence of one equivalent of NaOH or by reacting 2-mercapto-4,6-bis(isopropylamino)-5-triazine with a methylating agent in the presence of NaOH.
Prometryne is made either by reacting propazine with methyl mercaptan in the presence of one equivalent of NaOH or by reacting 2-mercapto-4,6-bis(isopropylamino)-5-triazine with a methylating agent in the presence of NaOH.

Definition

ChEBI: A diamino-1,3,5-triazine that is N,N'-di(propan-2-yl)-1,3,5-triazine-2,4-diamine substituted by a methylsulfanediyl group at position 6.

General Description

Colorless crystals. Used as an herbicide.

Reactivity Profile

A triazine derivative. Amines are chemical bases. They neutralize acids to form salts plus water. These acid-base reactions are exothermic. The amount of heat that is evolved per mole of amine in a neutralization is largely independent of the strength of the amine as a base. Amines may be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated by amines in combination with strong reducing agents, such as hydrides.

Flammability and Explosibility

Not classified

Agricultural Uses

Herbicide: Prometryn is used to control several annual grasses and broadleaf weeds in terrestrial food and feed crops. Its major uses are on cotton and celery, and is often used on dill and pigeon peas. Not approved for use in EU countries. Registered for use in the U.S.

Trade name

A-1114®; CAPAROL®; COTTON PRO®; G 34161®; GESAGARD®; MERCASIN®; MERCAZIN®; MERKAZIN®; POLISIN®; PRIMAPIN®; PRIMATOL-Q®; PROMET®; PROMETREX®; SELECTIN®; SELECTIN-50®; SELEKTIN®; SESAGARD®; SUPREND®; UVON®

Potential Exposure

Prometryn, a triazine herbicide, is used to control several annual grasses and broadleaf weeds in terrestrial food and feed crops. Among its major applica- tions are on cotton and celery and is often used on dill and pigeon peas.

Carcinogenicity

No carcinogenic activity was seen in either the rat or the mouse following lifetime feeding of up to 1500 or 3000 ppm, respectively.

Environmental Fate

Soil. In soil and plants, the methylthio group is oxidized. The proposed degradative pathway is the formation of the corresponding sulfoxide and sulfone derivatives of prometryn followed by oxidation of the latter to forming hydroxypropazine (Kearney and Kaufman, 1976). Cook and Hütter (1982) reported that bacterial cultures degraded prometryne to form the corresponding hydroxy derivative (hydroxyprometryne). 14C-Prometryn was incubated in an organic soil for one year. It was observed that 57.4% of the bound residues were comprised of prometryn (>50%), hydroxypropazine, mono-n-dealkylated prometryn, mono-N-dealkylated hydroxypropazine, a didealkylated compound [2-(methylthio)-4-amino-6-(isopropylamino)-s-triazine] and unidentified methanol soluble products (Khan and Hamilton, 1980; Khan, 1982). Hydroxyprometryn and ammeline were reported as hydrolysis metabolites in soil (Somasundaram et al., 1991). The reported halflife in soil is 60 days (Jury et al., 1987).
Photolytic. When prometryn in aqueous solution was exposed to UV light for 3 hours, the herbicide was completely converted to hydroxypropazine. Irradiation of soil suspensions containing prometryn was found to be more resistant to photodecomposition. About 75% of the applied amount was converted to hydroxypropazine after 72 hours of exposure (Khan, 1982). The UV (λ = 253.7 nm) photolysis of prometryn in water, methanol, ethanol, n-butanol and benzene, yielded 2-methylthio-4,6-bis(isoprop-ylamino)-s-triazine. At wavelengths >300 nm, photodegradation was not observed (Pape and Zabik, 1970). Khan and Gamble (1983) also studied the UV irradiation (λ = 253.7 nm) of prometryn in distilled water and dissolved humic substances. In distilled water, 2-hydroxy-4,6-bis(isopropylamino)-s-triazine and 4,6-bis(isopropylamino)-s-triazine formed as major products.
In the presence of humic/fulvic acids, 4-amino-6-(isopropylamino)-s-triazine was also formed (Khan and Gamble, 1983). Pelizzetti et al. (1990) studied the aqueous photocatalytic degradation of prometryn and other s-triazines (ppb level) using simulated sunlight (λ >340 nm) and titanium dioxide as a photocatalyst. Prometryn rapidly degraded forming cyanuric acid, nitrates, sulfates, the intermediate tentatively identified as 2,4-diamino-6- hydroxy-N,N′-bis(1-methyl-ethyl)-1,3,5-triazine and other intermediate compounds similar to those found for atrazine. It was suggested that the appearance of sulfate ions was due to the attack of the methylthio group at the number two position. Mineralization of cyanuric acid to carbon dioxide was not observed (Pelizzetti et al., 1990).
Chemical/Physical. Mascolo et al. (1995) studied the reaction of prometryn (100 μM) with sodium hypochlorite (10 mM) at 25°C and pH 7. Degradation followed the following pathway: prometryn → 2,4-(N,N′-diisopropyl)diamino-6-methylsulfinyl-1,3,5-triazine → 2,4-(N,N′-diisopropyl)diamino-6-methylsulfonyl-1,3,5-triazine → 2,4-(N,N′-diisopropyl)diamino-6-methanesulfonate ester 1,3,5-triazine → 2,4-(N,N′-diisopropyl)diamino-6- hydroxy-1,3,5-triazine.

Shipping

Triazine pesticides, solid, toxic, n.o.s. require a shipping label of “poisonous materials.” This material fall in DOT/UN Hazard Class 6.1.

Toxicity evaluation

Toxicity class II or III, slightly to moderately toxic (depending on formulation)

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinera- tor equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed. In accordance with 40CFR165, follow recom- mendations for the disposal of pesticides and pesticide containers. Containers must be disposed of properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.