FENCHLORPHOS

Powder or granules. Insoluble in water; soluble in most organic solvents.

Insecticide.

White to light-tan crystalline solid. Mp: 41° C, Density :1.49 g cm-3 at 25°C. Biocidal (toxic to all animal life in differing degrees) by its action as a cholinesterase inhibitor. Used as an insecticide. Degrades readily in the environment by hydrolysis and oxidation.

FENCHLORPHOS is non-flammable and non-combustible. Decomposes with heating to evolve toxic and corrosive vapors (hydrogen chloride, phosphorus oxides, sulfur oxides). Incompatible with strong oxidizing agents.

Toxic by ingestion and inhalation. Cholinesterase inhibitor, use may be restricted. Questionable carcinogen.

Ronnel is a weak cholinesterase inhibitor and has low toxicity. On both single and repeated doses, ronnel affects the pseudoesterase of the plasma rather than the true acetylcholinesterase of the red blood cells.Ronnel has not been shown to potentiate the effect of other commonly used organophosphorus insecticides.

Poison by ingestion and intraperitoneal routes. Moderately toxic by skin contact. A cholinesterase inhibitor. An experimental teratogen. Experimental reproductive effects. Human mutation data reported. When heated to decomposition it emits very toxic fumes of Cl-, POx, and SOx. See also PARATHION and CHLOROPHENOLS.

Ronnel is both an organochlorine and organophosphorus compound; potential danger to those involved in manufacture, formulation and application of this insecticide for farm (livestock) and household uses. Degrades readily in the environment by hydrolysis and oxidation .

Chemical/Physical. Though no products were identified, the reported hydrolysis halflife at pH 7.4 and 70°C using a 1:4 ethanol/water mixture is 10.2–10.4 hours (Freed et al., 1977). Ronnel decomposed at elevated temperatures on five clay surfaces, each treated with hydrogen, calcium, magnesium, aluminum and iron ions. At temperatures <950°C (125, 300 and 750°C), bentonite clays impregnated with technical ronnel (18.6 wt %) decomposed to 2,4,5-trichlorophenol and a rearrangement product tentatively identified as O-methyl S-methyl-O-(2,4,5-trichlorophenyl) phosphorothioate (Rosenfield and Van Valkenburg, 1965). At 950°C, only the latter product formed. It was postulated that this compound resulted from an acid-catalyzed molecular rearrangement reaction. Ronnel also undergoes base-catalyzed hydrolysis at elevated temperatures. Products include methanol and a new compound that is formed via cleavage of a methyl group from one of the methoxy groups, which is then bonded to the sulfur atom (Rosenfield and Van Valkenburg, 1965).
Ronnel is stable to hydrolysis over the pH range of 5–6 (Mortland and Raman, 1967). However, in the presence of a Cu(II) salt (as cupric chloride) or when present as the exchangeable Cu(II) cation in montmorillonite clays, ronnel is completely hydrolyzed via first-order kinetics in <24 hours at 20°C. The calculated half-life of ronnel at 20°C for this reaction is 6.0 hours. It was suggested that decomposition in the presence of Cu(II) was a result of coordination of the copper atom through the oxygen or sulfur on the phosphorus atom resulting in the cleavage of the side chain containing the phosphorus atom forming O,O-ethyl-O-phosphorothioate and 1,2,4-trichlorobenzene (Mortland and Raman, 1967).
Emits very toxic fumes of chlorides, sulfur and phosphorus oxides when heated to decomposition (Lewis, 1990).

UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN2783 Organophosphorus pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

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, and epoxides. Store at temperatures ＜25-30℃. Organothiophosphates are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrideds and active metals. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides

Incineration with added flam- mable solvent in furnace equipped with afterburner and alkali scrubber . In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesti- cide containers. Must be disposed properly by following package label directions or by contacting your local or fed- eral environmental control agency, or by contacting your regional EPA office.