Mustard Gas

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Mustard Gas Brittany Kaufman, Andy Schwert, Karyn Jones, JoAnna Lindberg

The Creation of Mustard Gas

Mustard gas was first synthesized from ethylene and SCl₂ by Frederick Guthrie in 1860.⁵ The harmful effects of mustard gas was first realized when Guthrie’s skin blistered in reaction to coming into contact with the gas. Yet, the true devastating effects of Mustard gas weren’t felt until the time of WWI when Nazi Scientists began to experiment with the dangerous gas.

The Historical Use of Mustard Gas

Mustard gas was first used by the Germans in WWI. The gas was specifically used by the Germans because it proved to be very useful in incapacitating their enemies. The Germans were more interested in wounding an enemy because it would slow an army down more so than a dead enemy. Mustard gas was extremely effective because of it’s chemical stability and persistence in the field. Mustard gas was extensively used in trench warfare. It was particularly used as an area-denial weapon, which forced soldiers to abandon the surrounding area. That area was then left unusable because of Mustard gas’ unique ability to remain in the soil once it would come into contact with the Earth. It would linger in areas of low geography for long periods of time once it was dispersed. Not only was Mustard gas undeniably damaging, but it was even more drastic because gas masks proved to be quite useless.

Chemical

The chemical name of mustard gas is 1,1-thiobis(2-chloroethane), but is also known as H, pyrite or Kampstoff Lost.⁵ When the agent is in its impure form the odor takes on a mustard or horseradish smell, hence the common name mustard gas. Yet, in its pure form mustard gas is in fact odorless and colorless. The chemical formula is relatively simple: ClCH₂CH₂SCH₂CH₂Cl. On the other hand, the reaction of mustard gas is not as simple. Participation of the sulfur atom leads to displacement of chorine as a leaving group that results in a 3 membered cyclic sulfonium intermediate, called an episulfonium ion. Water or protein found on the skin can then nucleophilically attack this electrophilic ion, an electrophilic ion is a chemical compound that is attracted to electrons and tends to accept electrons. This nucleophilic attack creates an alcohol. The chlorine that is now free can then take a hydrogen from the water and create 2-(2-Chloro-ethylsulfanyl)-ethanol and hydrochloric acid.⁵ Since mustard gas begins with two chlorines on both ends the new alcohol molecule can undergo the reaction again to form 2-(2-Hydroxy-ethylsulfanyl)-ethanol and more hydrochloric acid.⁷ For each molecule of mustard gas that undergoes this reaction, two molecules of hydrochloric acid are made. This results in high concentrations of acid on the surface of the reaction site, which is commonly the skin or lungs. Below is the reaction mechanism of mustard gas.

Effects

Mustard Gas can be very damaging especially to the skin, eyes, and respiratory system. The effects of the gas can be detected one hour from exposure but severe symptoms do not develop until after 24 hours.^[1] If it is ingested the individual may suffer from vomiting and diarrhea.¹ If it is inhaled and absorbed through skin, the immediate effects include: nausea, vomiting, eye inflammation, secretion of tears, and runny nose.¹ Six to Twenty-Four hours later, these symptoms worsen and blisters become more of a nuisance.¹ Usually the long term damage of the skin is not caused merely by blisters, but by the itching associated with them. Depending on how long the person has been exposed, they may also become blind.¹ Mustard Gas is very soluble in fat, but not soluble in water.⁴ This makes the gas easily absorbed into the skin, causing the blisters. It also suppresses bone marrow by lowering the number of white blood cells.^[2] Mustard Gas exposure is usually not fatal. Only 5% of those treated for mustard gas in WWI died.^[3] If a person is continually exposed, they may develop cancer. This is because ClCH₂CH₂ readily forms a sulfonium ion that bonds to guanine in DNA strands.^[4] It also bonds with the RNA and proteins in the body. The treatment for mustard gas exposure is to flush it out and off the body. It cannot be washed off with water because of its insolubility with it.^[5] Instead it is removed from the skin with a super-chlorinated bleach like NaOCl^- or (CaCOCl^-)₂. It can also be removed with peroxy acids, such as C₇H₁₅COOH.^vIf ingested, the person should try to drink milk instead of vomiting.¹

Environment

Mustard gas was originally used as a chemical warfare agent and was released directly to the atmosphere in countries outside the United States. From World War I until 1970 Mustard gas was disposed of all over the world, consequently, it is found in ocean waters and in the ground all over the world.⁶ Studies have shown that mustard gas can stay underground for a certain time period, depending on environment conditions. When humans come in contact with it the results can be deadly. World Health Organization reports a persistence of mustard gas for 12 to 48 hours at 100^o C with rain and a moderate wind, 2 to 7 days at 15^o C with sun and a light breeze, and 2 to 8 weeks at –10^o C with snow cover.⁶ Readings of ground contamination have shown that in some areas mustard gas has been found in the soil for 10 years.⁶ Natural degradation of mustard gas in soil is a result of chemical hydrolysis and biodegradation. Chemical hydrolysis depends on the soil and moisture content, along with degree of contamination and temperature. In soil and water, some mustard gas evaporates into the air and the rest breaks down in either minutes or days depending on environmental conditions. Most of the time when it breaks down it reacts with chemicals in the air to form other compounds. The compounds that it forms with have been shown to have no negative effects on the environment.

Footnotes

1. ^ Walton, Perharic L. , Dr.; Maynard, R. L. , Dr.; Murray, U. S. G. , Dr. Chemical Safety Information From Intergovernmental Organizations: Mustard Gas. http://www.inchem.org/documents/pims/chemical/mustardg.htm (accessed 9/25, 2005).
2. ^ Agency for Toxic Substances & Disease Registry (ATSDR)
3. ^ Centers For Disease Control and Prevention: Facts about Mustard Gas. http://www.bt.cdc.gov/agent/sulfurmustard/basics/facts.asp (accessed 9/27, 2005).
4. ^ Mustard Gas. http://www.reference.com/browse/wiki/Mustard_gas (accessed 9/25, 2005).
5. ^ Holland, R. Mustard Gas. http://www.bristol.ac.uk/Depts/Chemistry/MOTM/mustard/mustard.htm (accessed 10/16, 2005).
6. World Heath Organization. “Environmental effects of Mustard Gas” (2004). www.hpa.org.uk/infections/topics_az/deliberate_release/chemicals/mustard_gas (accessed 10/04, 2005)
7. Agg, Stephen. The History of Chemical Warfare. Mustard Gas. http://www..chem.shef.ac.uk/chm131-2002/cha02sra/mustard_gas.html. (accessed 09/25, 2005.)