Diphosgene

diphosgene (dī'fŏz`jēn), colorless liquid developed as a military poison. It boils at 128°C;; its vapors have the odor of phosgene. Diphosgene is a lung irritant but is only slightly lachrimatory. Like phosgene, its effects are often delayed. Chemically it is trichloromethylchloroformate, ClCO₂CCl₃.

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diphosgene [dī′fäz‚jēn]

(organic chemistry)

trichloromethyl chloroformate

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Diphosgene 

trichloromethyl chloroformate, , a colorless, heavy mobile liquid, which fumes slightly in air and has a characteristic smell of rotting hay. Melting point, -57°C; boiling point, 128°C; d₄¹⁵, 1.644; index of refraction n_D²⁰, 1.4566. It is poorly soluble in water but readily soluble in organic solvents. It is slowly hydrolyzed by water; the hydrolysis is considerably accelerated by heat and alkalies. Diphosgene reacts vigorously with ammonia and amines, yielding urea or its derivatives. The reaction can be used in diphosgene decontamination. At 300°-350°C, as well as in the presence of AlCl₃, FeCl₃, and other metal halides, diphosgene decomposes to COCl₂, CO, and CCl₄. Diphosgene is made by the exhaustive chlorination (under illumination) of methyl chloroformate.

Diphosgene has a powerful asphyxiating action and an appreciable irritant action. The unendurable concentration is 0.075 mg per liter; the fatal concentration, 0.25 mg per liter (30 min exposure). Diphosgene poisoning is characterized by a latent period of action (up to 6-8 hrs). Prolonged exposure to low concentrations is very dangerous, and the overall effect can result in marked damage to the organism (so-called cumulative effect). In World War I it was used as a poison.

REFERENCES

Soborovskii, L. Z., and G. Iu. Epshtein. Khimiia i tekhnologiia boevykh khimicheskikh veshchestv. Moscow-Leningrad, 1939.
Fliuri, F., and F. Tsernik. Vrednye gazy. Moscow, 1938.

R. N. STERLIN