dichloroformoxine

Description

Phosgene oxime is a colourless solid or yellowish-brown liquid with a disagreeable penetrating odour. Pure phosgene oxime is a colourless, crystalline solid; the munitions grade compound is a yellowish-brown liquid. Phosgene oxime is soluble in water and organic solvents, but hydrolyses rapidly, and especially in the presence of alkali. Chemically similar to but more reactive than an amide. Incompatible with strong acids and bases, and especially incompatible with strong reducing agents such as hydrides. It is also incompatible with strongly oxidising acids, peroxides, and hydroperoxides. Phosgene oxime is a very severe blistering agent. Both the liquid and the solid can give off vapours at ambient temperatures. Phosgene oxime was developed as a potential chemical warfare agent but has never been known to be used on the battlefield. Phosgene oxime (CX) is an urticant or nettle agent causing instant intolerable pain, erythema, wheals, and urticaria. It is very corrosive, capable of causing extensive tissue damage. Phosgene oxime was first produced by the Germans in 1929 as a possible warfare agent. The mechanism of action is not fully understood but the lesions produced in the skin are similar to those caused by a strong acid. Phosgene oxime will penetrate ordinary clothing and surgical gear.

Chemical Properties

Phosgene oxime (military designation CX) is a non-combustible urticant (nettle agent, blister agent) with a short (seconds to minutes) latency period. CX is a colorless, low-melting point (crystalline, white powder) solid or as a liquid (liquid above 39C; solid below 35C). On hot days (or at body temperature) it can appear as a yellowishbrown liquid. It has a high vapor pressure (the vapor pressure of the solid is high enough to produce symptoms), slowly decomposes at normal temperatures. It has an intense, disagreeable,penetrating, and violently irritating, peppery odor. Odor detectable at less than 0.3 ppm.

Uses

There are no commercial or beneficial uses of phosgene oxime. It was developed and produced solely as a chemical warfare agent, but has never been used on the battlefield.

General Description

Colorless liquid, odorless to fruity.

Reactivity Profile

dichloroformoxine is an oxime. Chemically similar to, but more reactive than an amide. Incompatible with strong acids and bases, and especially incompatible with strong reducing agents such as hydrides. Also incompatible with strongly oxidizing acids, peroxides, and hydroperoxides.

Health Hazard

Median lethal dose (mg-min/m3): 3200 (inhaled). Median incapacitating dose: Very low. Eye/skin toxicity: Powerful irritant to eyes and nose; liquid corrosive to skin. Rate of action: Immediate effects on contact. Physiological action: Violently irritates mucous membranes, eyes and nose; forms wheals rapidly. (ANSER)

Potential Exposure

There’s no industrial use for Phosgene oxime (CX) and because of its extreme instability, the pure material is not likely to be used in military operations. CX is especially dangerous when mixed with other chemicals such as nerve agents. It burns away the skin making it more permeable to any other “added” agents. No other chemical agent is capable of producing immediate extreme pain followed by rapid local tissue death (necrosis). Post World War II studies indicate that concentrations below 8% cause no or inconsistent effects.

Environmental Fate

Phosgene oxime does not accumulate in the soil since both phosgene oxime and the parent compound of phosgene have been shown to be highly unstable in the environment. Small amounts which may be present can vaporize into the air or be degraded by soil bacteria. Once in vapor form, phosgene oxime remains in vapor form and will be inactivated by compounds in the atmosphere or broken down by bacteria. There is no evidence that phosgene oxime will accumulate in groundwater. Phosgene oxime is fairly soluble in water and if exposed to soil moisture may rapidly decompose to CO2, HCl, and hydroxy amine hydrochloride.

Shipping

UN2811 (solid)/UN2810 (liquid) Toxic solids or liquids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1Poisonous materials, Technical Name Required. Military driver shall be given full and complete information regarding shipment and conditions in case of emergency. AR 50-6 deals specifically with the shipment of chemical agents. Shipments of agent will be escorted in accordance with AR 740-32.

Toxicity evaluation

The molecular mechanism of phosgene oxime toxicity is unknown. Phosgene oxime is the least well studied of all vesicant/urticant compounds but possible mechanisms may involve the actions of (1) necrotizing effects of chlorine, (2) direct toxic effects of oxime, and/or (3) the actions of carbonyl groups on the target tissue. One hypothesis is that phosgene oxime toxicity can be broken down into two mechanisms. First is a direct mechanism which will involve direct enzymatic inactivation, cell death, corrosive injury, and rapid destruction of the tissue that phosgene oxime has contacted. Secondarily, there are a series of indirect mechanisms that may increase tissue injury. There is activation of alveolar macrophages, recruitment of neutrophils to the damage site, release of hydrogen peroxide, and then delayed disuse injury following the edema associated with phosgene oxime exposure.

Incompatibilities

Phosgene oxime (CX) is among the most important halogenated oximes. CX reacts with water, sweat, and heat, forming hydrochloric acid. CX may be an oxidizer, and it may ignite combustibles, e.g., wood, paper, oil, or clothing). CX is incompatible with strong acids and bases; hydrides and other strong reducing agents such as hydrides; strong oxidizing acids, peroxides, and hydroperoxides. Not hydrolyzed by dilute acids; reacts violently in basic solutions forming carbon dioxide, hydrogen chloride, and hydroxylamine. Hydrolysis products include HCl and methylarsenic oxide. CX quickly penetrates rubber and clothing. Traces of many metals cause it to decompose; however, it corrodes most metals. Oximes are chemically similar to, but more reactive than amides. Incompatible with strong acids and bases, and especially incompatible with strong reducing agents such as hydrideds and active metals. Also incompatible with strongly oxidizing acids, peroxides, and hydroperoxides. CX decomposes when in contact with many metals; it is corrosive to most metals, and contact with metals may evolve flammable hydrogen gas.

Waste Disposal

Seek expert advice from armed services (see Reference section), Center for Disease Control headquarters in Atlanta, Ga.