Sulfur mustards types

Another interesting reaction is cyclization with halide elimination. The case of formation of aziridinium rings from A-(2-chloroethyl) derivatives (nitrogen mustards) has been reviewed in Sect. 11.4.2, as was sulfur mustard. The remainder of this subsection is devoted to comparable reactions in which the product is not a strongly electrophilic aziridinium ion, but another ring type. 

The final type of chemical toxicity that will be presented are the vesicants, chemicals that cause blisters on the skin. There are two classes of blisters that implicate different mechanisms of vesication. Intraepidermal blisters are usually formed due to the loss of intercellular attachment caused by cytotoxicity or cell death. The second class occurs within the epidermal-dermal junction (EDJ) due to chemical-induced defects in the basement membrane components. The classic chemical associated with EDJ blisters is the chemical warfare agent sulfur mustard (bis-2-chloroethyl sulfide HD). HD is a bifunctional alkylating agent that is highly reactive with many biological macromolecules, especially those containing nucleophilic groups such as DNA and proteins. 

Sulfur mustard can be very persistent in soil (Rosenblatt et al., 1995). Persistence depends on the soil type, pH, moisture content, and whether the agent is at the soil surface or buried. Small (1984) reported that when HD was applied to the soil surface, volatilization would be the main route of HD loss (half-life about 30 min), but if the soil was wet, hydrolysis would be the main loss pathway. When sprayed onto soil, a vesicant action was still apparent after about 2 weeks when the agent leaked into the soil, however, a vesicant action was still present after 3 years (DA, 1974). Rosenblatt et al. (1995) state that the persistence of sulfur mustard in soil is due to the formation of oligomeric degradation products that coat the surface of the mustard agent and that are resistant to hydrolysis. 

The skin and eyes are especially sensitive to the toxic effects of sulfur mustard. When applied to human skin, about 80% of the dose evaporates and 20% is absorbed (Vogt et al., 1984). About 12% of the amount absorbed remains at the site and the remainder is distributed systemically (Renshaw, 1946). Doses up to 50 pg/ cm cause erythema, edema, and sometimes small vesicles. Doses of 50-150 pg/cm cause bullous-type vesicles, and larger doses cause necrosis and ulceration with peripheral vesication. Droplets of liquid sulfur mustard containing as little as 0.0025 mg may cause erythema (Ward et al., 1966). Eczematous sensitization reactions were reported in several early studies and may occur at concentrations below those causing direct primary irritation (Rosenblatt et al., 1975). In humans, the LCtso (estimated concentration x exposure period lethal to 50% of exposed individuals) for skin exposures is 10,000 mg-min/m (DA, 1974) (for masked personnel however, the amount of body surface area exposed was not reported). The ICt 50 (estimated concentration x exposure period incapacitating to 50% of exposed individuals) for skin exposures is 2000 mg-min/m at 70-80°F in a humid enviromnent and 1000 mg-min/m at 90°F in a dry enviromnent (DA, 1974, 1992). The ICtso for contact with the eyes is 200 mg-min/m (DA, 1974, 1992). The LDl for skin exposure is 64 mg/kg and the LD50 is estimated to be about 100 mg/kg (DA, 1974,1992). 

CWAs have been widely eondemned since they were first used on a massive scale during World War I. However, they are still stockpiled and used in many countries as they are cheap and relatively easy to produee, and can cause mass casualties. Although the blood agent CK is extremely volatile and undergoes rapid hydrolysis, the degradation of three types of vesicant CWAs, the sulfur mustards, nitrogen mustards, and Lewisite, results in persistent products. For... 

Analysis of Blood Samples. Urinary metabolites undergo relatively rapid elimination from the body, whereas blood components offer biomarkers that have the potential to be used for verification of sulfur mustard exposure long after the exposure incident. Three different approaches have been used for blood biomarker analysis. The intact macromolecule such as protein or DNA with the sulfur mustard adducts still attached can be analyzed. To date, this approach has only been demonstrated for hemoglobin using in vitro experiments. For proteins, an alternate approach is to enzymatically digest them to produce a smaller peptide with the sulfur mustard adduct still attached. Methods of this type have been developed for both hemoglobin and albumin. A third approach has been to cleave the sulfur mustard adduct from the macromolecule and analyze in a fashion similar to that used for free metabolites found in the urine. The later two approaches have both been successfully used to verify human exposure of sulfur mustard. 

There is one other key point concerning sulfur mustard. Pure sulfur mustard (HD) freezes at about 58°F. Once frozen, essentially no mustard vapor is released. Consequently, electronic monitoring relying on detection of released mustard vapor would be useless, and contamination of persons exposed to frozen sulfur mustard would not be detected by this type of monitoring. Upon rewarming, both liquid and vapor sulfur mustard would be present on the contaminated clothing. 

Phase I testing was carried out from April to September 2003 (Blades et al., 2004). A variety of munition types containing sulfur mustard agent, phosgene, a phosgene-chloropicrin mixture, and a smoke composition were destroyed. 

The physical, chemical and hazardous properties of a number of highly toxic or flammable substances that were in the past or being currently used in the warfare have been discussed in detail in several chapters in this book. Some of these compounds are further discussed under specific chapters, such as. Sulfur Mustards, Nerve Gases, Dioxin and Related Compounds and Napalm. These and many other compounds are in most cases grouped together in this book based on their chemical structures along with their toxic or flammable properties. Presented below is a brief discussion on various types of chemicals weapons developed for military applications. Explosive substances have been omitted from this section. They are discussed separately in this book under topics such as Explosive Characteristics of Chemical Substances, Nitro Explosives, Oxidizers and Organic Peroxides and also under specific title compounds in various chapters. 

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. 

There are two types of mustard sulfur mustard and nitrogen mustard. An impure sulfur mustard was probably synthesized by Despretz in 1822, but it was not identified. Riche, in 1854, and Guthrie, several years later, repeated Despretz s reaction to obtain the same product. Guthrie described the product as smelling like mustard, tasting like garlic, and causing blisters after contact with the skin. Niemann, in 1860, also synthesized the compound. 

Sulfur mustard is a type of chemical warfare agent. These kinds of agents are called vesicants or blistering agents, because they cause blistering of the skin and mucous membranes on contact. 

There are two types of mustard agents, sulfur mustards and nitrogen mustards the general structural formula of these compounds is as follows ... 

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