Sulfur mustard agents, physical/chemical

Sulfur mustards are oxidized with strong oxidants and are hydrolyzed with alkali, generally producing reaction products that are less toxic. Reactions with chlorine or chlorinating agents such as NaOCl or Ca(OCl)2 yield nontoxic products. This reaction is suitable to inactivate and decontaminate sulfur mustards. The physical, chemical, and toxic properties of mustard gas and a few selective compounds of this class are outline below. 

Watson and Griffin (1992) have summarized information on the distribution of unitary chemical weapon stockpiles in the USA. The chemical and physical properties of sulfur mustard (agent HD) are shown in Table 8.2. 

The fate of HD in the environment is determined by its chemical and physical properties. Observations of persistence and degradation products from both field and laboratory studies support the characterization of HD as a persistent agent. As noted, sulfur mustard is a liquid at ambient temperatures the vapor pressure is low (0.11 mmHg at 25°C), but sufficient for mustard to be in the air immediately surrounding droplets of the liquid. The primary dissipation mechanism for HD from soil is evaporation. Sulfur mustard vapor is 5.5 times heavier than air, and evaporation or volatilization from surfaces or soils is projected to require days at temperatures above its freezing point (Puzderliski, 1980). Below its... 

The term blister agents includes a wide range of compounds with diverse physical and chemical properties and chemical structures. They may be broadly grouped under a few general types, namely, the sulfur mustards, nitrogen mustards and organochloro-arsines. There are also some substances that do not fall nnder the above categories. 

Physiological Effects. The sulfur and nitrogen mustards act first as cell irritants and finally as a cell poison on all tissue surfaces contacted. The first symptoms usually appear in 4—6 h (4). The higher the concentration, the shorter the interval of time between the exposure to the agent and the first symptoms. Local action of the mustards results in conjunctivitis (inflammation of the eyes) erythema (redness of the skin), which may be followed by blistering or ulceration and an inflammatory reaction of the nose, throat, trachea, bronchi, and lung tissue. Injuries produced by mustard heal much more slowly and are much more Fable to infection than bums of similar intensity produced by physical means or by other chemicals. 

Various other chemical agents which by their nature are capable of producing cross-linkages between polymer chains effect the same changes in physical properties that are observed in sulfur vulcanization. One of the best known of these agents is sulfur monochloride, which readily combines with two molecules of an olefin (the mustard gas reaction). Applied to rubber, it induces vulcanization even at moderate temperatures, the probable structure of the cross-linkage being... 

---