| Description | Paraquat dichloride is a dark blue liquid, non-combustible, stable herbicide chemical. It isincompatible with strong oxidising agents. On contact with fire paraquat decomposes givesoff irritating or toxic fumes (or gases), nitrogen oxides, and hydrogen chloride. Paraquatdichloride contact and storage destroys metal. Paraquat dichloride hydrolyses in alkalinemedia and reacts with aluminium to produce hydrogen gas.Paraquat (N,N′-dimethyl-4,4′-bipyridinium dichloride) is one of the most widely used herbicidesin the world. Paraquat dichloride is a herbicide currently registered to control weedsand grasses in many agricultural and non-agricultural areas. It is used preplant or preemergenceon vegetables, grains, cotton, grasses, sugar cane, peanuts, potatoes, and tree plantationareas; post-emergence around fruit crops, vegetables, trees, vines, grains, soybeans,and sugar cane. It is also used on non-crop areas such as public airports, electric transformerstations, and around commercial buildings to control weeds. It has been reported that aboutseven pesticide products are registered which contain the active ingredient paraquat dichlorideand classified as restricted use pesticides (RUPs). Paraquat dichloride and the productsare primarily intended for ‘Occupational Use’. In the United States, Paraquat is classified as‘restricted commercial use’, and people must obtain a license to use the product. |
| Chemical Properties | Paraquat is a yellow solid with a faint,ammonia-like odor. |
| Chemical Properties | off-white powder |
| Definition | ChEBI: Paraquat dichloride is an organic chloride salt. It has a role as a herbicide and a photosystem-I inhibitor. It contains a paraquat. |
| General Description | Colorless to yellow crystalline solid. Used as a contact herbicide and desiccant. |
| Air & Water Reactions | Water soluble. |
| Reactivity Profile | Paraquat dichloride is stable in acidic media, but unstable in alkaline media. Paraquat dichloride is photochemically decomposed by UV irradiation in aqueous solutions and is rapidly inactivated by soil. The neat chemical may be sensitive to light. Paraquat dichloride is corrosive to metal and Paraquat dichloride can react with strong acids, bases, and oxidizing agents. Paraquat dichloride is hydrolyzed by alkali compounds and Paraquat dichloride is inactivated by inert clays and anionic surfactants. |
| Health Hazard | Can cause death due to severe injury to the lungs. The lowest lethal oral dose reported in humans is 43 mg/kg. |
| Fire Hazard | Avoid strong oxidizers. |
| Flammability and Explosibility | Not classified |
| Contact allergens | Paraquat is a quaternary ammonium compound with herbicideproperties, as diquat. It is contained in Cekuquat? orDipril?. It can cause contact and phototoxic contact dermatitis,acne, and leukoderma mainly in agricultural workers. |
| Safety Profile | A human poison by ingestion. Poison experimentally by ingestion, skin contact, intraperitoneal, intravenous, and subcutaneous routes. Human systemic effects by ingestion: acute renal failure, acute tubular necrosis, cough, diarrhea, dyspnea, headache, hyp |
| Potential Exposure | Those engaged in manufacture,formulation and application of this herbicide. Classifiedfor restricted use: limited to use by a certified applicator, orthose under applicator’s direct supervision. |
| Shipping | UN2781 Bipyridilium pesticide, solid, toxic,Hazard Class: 6.1; Labels: 6.1-Poisonous materials. |
| Purification Methods | Recrystallise the dichloride from MeOH/acetone mixture. It has also been recrystallised three times from absolute EtOH [Bancroft et al. Anal Chem 53 1390 1981]. Dry it at 80o in a vacuum. [Beilstein 23/8 V 30.] |
| Incompatibilities | Incompatible with oxidizers (chlorates,nitrates, peroxides, permanganates, perchlorates, chlorine,bromine, fluorine, etc.); contact may cause fires or explosions.Keep away from alkaline materials, strong bases,strong acids, oxoacids, epoxides (hydrolysis), alkylarylsulfonatewetting agents. Corrosive to metals. Decomposesin presence of ultraviolet (UV) light. Decomposes in heat(see physical properties, above) and in the presence of UVlight, producing nitrogen oxides, hydrogen chloride. |
| Waste Disposal | Paraquat is rapidly inactivatedin soil. It is also inactivated by anionic surfactants.Therefore an effective and environmentally safe disposalmethod would be to mix the product with ordinary householddetergent and bury the mixture in clay soil. Inaccordance with 40CFR165, follow recommendations forthe disposal of pesticides and pesticide containers. Must bedisposed properly by following package label directions orby contacting your local or federal environmental controlagency, or by contacting your regional EPA office. Consultwith environmental regulatory agencies for guidance onacceptable disposal practices. Generators of waste containingthis contaminant (≥100 kg/mo) must conform withEPA regulations governing storage, transportation, treatment,and waste disposal. |
