Paraquat
Trade and Other Names: Product names include Crisquat, Cyclone, Dextrone, Dexuron, Gramoxone Extra, Herbaxone, Ortho Weed and Spot Killer, and Sweep. The compound may be found in formulations with many other herbicides, including simazine and diquat dibromide.
Chemical Class: quaternary nitrogen compound
Introduction: Paraquat is a quaternary nitrogen herbicide widely used for broadleaf weed control. It is a quick-acting, nonselective compound, that destroys green plant tissue on contact and by translocation within the plant. It has been employed for killing marijuana in the U.S. and in Mexico. It is also used as a crop desiccant and defoliant, and as an aquatic herbicide.
Physical Properties:
Appearance: Paraquat salts are colorless, white, or pale yellow crystalline solids, which are hygroscopic and odorless.
Chemical Name: 1,1'-dimethyl-4,4'-bipyridinium
CAS Number: 1910-42-5
Molecular Weight: 257.20
Water Solubility: 700,000 mg/L @ 20 C
Solubility in Other Solvents: Dichloride salt is sparingly soluble in lower alcohols
Melting Point: Decomposes @ 300 C
Vapor Pressure: Negligible @ room temperature (paraquat dichloride)
Partition Coefficient: 4.4683
AdsorptionCoefficient: 1,000,000 (estimated)
Exposure Guidelines:
ADI: 0.004 mg/kg/day
MCL: Not Available
RfD: 0.0045 mg/kg/day
PEL: Not Available
HA: 0.03 mg/L (lifetime) TLV: 0.1 mg/m3 (8-hour) (respirable fraction)