9204. Tetraethyl Pyrophosphate

Nomenclature

CAS number: 107-49-3
Diphosphoric acid tetraethyl ester; pyrophosphoric acid tetraethyl ester; bis-O,O-diethylphosphoric anhydride; TEPP; Bladan (Bayer); Nifos T (Monsanto); Kilmite 40; Vapotone (Chevron); Tetron; Killax; Mortopal.
C8H20O7P2; mol wt 290.19.
C 33.11%, H 6.95%, O 38.59%, P 21.35%.

Description and references

Cholinesterase inhibitor. Prepd commercially by controlled hydrolysis of O,O-diethylphosphoric acid chloride: Kosolapoff, US 2479939 (1947 to Monsanto); Toy, J. Am. Chem. Soc. 70, 3882 (1948). Chemical history and comparison of various syntheses: G. Schrader, Die Entwicklung neuer insektizider Phosphors"aure-Ester (Verlag Chemie, Weinheim, 3rd ed., 1963) pp 68-79. Toxicity study: T. B. Gaines, Toxicol. Appl. Pharmacol. 14, 515 (1969).

Chemical structure

Properties

Mobile liquid. Agreeable odor. Hygroscopic. d420 1.185. Thermal decompn range 170-213° with copious formn of ethylene. bp0.05 82°; bp1.0 124°; bp2.3 138°. Vapor pressure at 30° = 4.7 × 10-4 mm Hg. nD20 1.4196. Misc with water, but quickly hydrolyzed by it (half life at 25° about 7 hrs in a 50 v/v mixt.). Also misc with acetone, methanol, ethanol, benzene, chloroform, carbon tetrachloride, glycerol, ethylene glycol, propylene glycol, toluene, xylene. Not misc with petr ether, kerosene, other petr oils. LD50 orally in male rats: 1.1 mg/kg (Gaines).

Caution

Potential symptoms of overexposure are eye pain, blurred vision, lacrimation, rhinorrhea, headache, tight chest and cyanosis; anorexia, nausea, vomiting and diarrhea; weakness, twitching, paralysis, Cheyne-Stokes respiration and convulsions; low blood pressure, cardiac irregularities; sweating. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 296.

Use

Insecticide.