Title:  Tetraethyl Pyrophosphate 
CAS Registry Number:  107-49-3 
CAS Name:  Diphosphoric acid tetraethyl ester 
Additional Names:  pyrophosphoric acid tetraethyl ester;  bis-O,O-diethylphosphoric anhydride;  TEPP 
Trademarks:  Bladan (Bayer);  Nifos T (Monsanto);  Kilmite 40;  Vapotone (Chevron);  Tetron;  Killax;  Mortopal 
Molecular Formula:  C8H20O7P2 
Molecular Weight:  290.19 
Percent Composition:  C 33.11%, H 6.95%, O 38.59%, P 21.35% 
Literature 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 Phosphorsäure-Ester (Verlag Chemie, Weinheim, 3rd ed., 1963) pp 68-79.  Toxicity study:  T. B. Gaines, Toxicol. Appl. Pharmacol. 14, 515 (1969). 
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). 
Boiling point:  bp0.05 82°; bp1.0 124°; bp2.3 138° 
Index of refraction:  nD20 1.4196 
Density:  d420 1.185 
Toxicity data:  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.   |