Chemistry and Warfare. The use of "Greek fire" Credit: Bridgeman Art Library

Chemistry and Warfare

The use of "Greek fire"

Credit: Bridgeman Art Library

Copyright © Houghton Mifflin Company. All rights reserved. 14 | 3

Learning Objectives

a. The ability to produce weapons that specifically target living organisms is closely tied to recent advances in chemistry.

b. Chemical weapons are classified according to mode of action, including lung irritants (such as chlorine gas), vesciants (such as mustard gas), respiratory poisons (such as cyanide), and nerve agents (such as VX).


Learning Objectives (cont)

c. Biological weapons, which are derived from living organisms, include viruses, bacteria, and toxic compounds found in nature.

d. Paradoxically, the same advances in our understanding of infectious agents that have led to a decrease in deaths from infectious disease have led to refinement of biological weapons.


Outline

• Early Use of Chemistry in Warfarea. Black Powder

1. An explosive mixture of potassium nitrate, charcoal, and sulfur developed by the Chinese in the 10th century. An alternate source of potassium nitrate is found in bird droppings.

b. High Explosives1. Exemplified by nitroglycerine or trinitrotoluene (TNT), which

contains internal nitro groups (-NO2) that rapidly oxidize the rest of the molecule

2. Detonation results from a volume expansion because of a rapid release of heat and gaseous products.


NO2

NO2

NO2

CH3

2,4,6-trinitrotoluene (TNT)

CH2 CH2CH

O

NO2 NO2

O

NO2

O

Nitroglycerine

High Explosives, which decompose entirely into gaseous products in a process called detonation.


Factors Affecting the Volume of a Gas


Fritz Haber(left,with Albert Einstein),a pioneer of gas warfare

Credit: AIP Emilio Segre Visual Archives

Fritz Haber (left) with Albert Einstein. Haber, who pioneered gas warfare, said on receiving his Nobel Prize, “In no future war will the military be able to ignore poison gas. It is a higher form of killing.”


Outline

• Early Use of Chemistry in Warfare (cont)c. Harassing Agents

1. Compounds such as teargas that temporarily incapacitate, rather than kill, the target

2. The first step towards lethal chemical warfarein World War I


Outline

• Chemical Warfare Agents a. Definition

1. Chemical substances, whether gaseous, liquid, or solid, which are used because of their direct toxic effects on humans, animals, or plants

b. Classes1. Classified by their mode of action: lung irritants,

vesicants, respiratory poisons, nerve agents, hallucinogens, and herbicides


Types ofChemical Warfare Agents

Classes of Chemical WeaponsChemical weapons are molecules that have selectively toxic effects on a living target.


Outline

• Chemical Warfare Agents (cont) c. Lung Irritants

1. Damage lung tissue directly or via a reaction to produce a corrosive compound

2. Exemplified by chlorine gas (Cl2)

3. Cl2 is a powerful oxidizing agent and also reacts with H2O in the lungs to form hypochlorous acid (HOCl), which oxidizes cellular molecules.

Lung irritants, or choking agents, damage cells within the bronchial passages, leading to leakage of fluid into the lungs


Examples of Lung Irritants


Action of Hypochlorous Acid (HOCl)


Chlorinegas attack in World War I

Credit: Corbis


Early gas masks worn by Allied troups, known as P-helmets

Credit: Corbis


Outline

• Chemical Warfare Agents (cont) d. Vesicants

1. Produce painful blisters on any exposed tissue

2. Exemplified by mustard gas

3. Use of mustard gas in warfare led to the discovery that certain related compounds are useful anticancer drugs because they damage DNA

Vesicants, which include mustard gas, produce painful burns and blisters on any exposed tissue.


Action of Nitrogen Mustard


Outline

• Chemical Warfare Agents (cont) e. Respiratory Poisons

1. Interfere with oxygen use at the molecular level

2. Exemplified by cyanide

3. Cyanide leads to rapid death by inhibiting cytochrome oxidase, an enzyme essential for ATP production during cellular respiration.

Respiratory poisons block an organism’s use of oxygen at the cellular level.


Action of Cyanide

Inactivates an enzyme essential for production of ATP through aerobic metabolism.


Outline

• Chemical Warfare Agents (cont) f. Nerve Agents

1. Inactivate the enzyme acetylcholinesterase, which is essential for muscle contraction. The result is rapid death by respiratory paralysis.

2. Exemplified by VX a new compound ideal for total destruction of a battlefield.

3. Atropine acts as an antidote for nerve agents by blocking the acetylcholine receptor.

Nerve agents block the normal transmission of nerve impulses from the brain to the muscles, leading to uncontrolled muscle contraction, convulsions, and respiratory paralysis.


Organophosphorus Nerve Gases


NicholasCage handling VX gas in The Rock

Credit: Zuma Press

In the movie The Rock (1996), biochemist Stanley Goodspeed is called in to help save San Francisco from a commando attack with VX gas. During his mission, he is exposed to the deadly chemical but fortunately is prepared with a syringe of atropine.


Action of Atropine

Atropine blocks the receptor for acetylcholine (ACh) so that no messages can be received by the muscle, thereby blocking the effects of a nerve agent.


Experimental drugs maybe factors in Gulf War syndrome

Credit: Corbis


Outline

• Chemical Warfare Agents (cont) g. Hallucinogens are compounds that cause an

individual to experience things that are not real.1. Harassing agents induce delusions and hallucinations

2. Exemplified by LSD

h. Herbicides are compounds that are selectively toxic to plants.

1. Selectively toxic to plants

2. Exemplified by Agent Orange


Credit: Data from Stockholm International Peace Research Institute (SIPRI), The Rise of CB Weapons, Vol. 1. Stockholm: SIPRI, 1971.

Chemical Agents Usedand Estimated Effects in World War I


In Europe, cleaning up explosives from both world wars continues

Credit: Zuma Press


Reported Cases ofPost-World War II Use of Chemical Weapons


Outline

• Biological Warfare Agents a. Definition

1. Living organisms such as bacteria or toxic material derived from them, which are intended to cause disease or death in humans, animals, or plants

b. Early Examples1. Disease-infected cadavers, blankets, and clothing

2. Poison arrows

Biological weapons are disease-causing agents such as bacteria and viruses or their toxic products


Outline

• Biological Warfare Agents (cont)c. Types of Modern Bioweapons

1. Bacteria: e.g., Bacillus anthracis, used by unknown parties to perpetrate the 2001 anthrax attacks.

2. Viruses: e.g., variola, which causes smallpox may be an emerging threat because individuals are no longer vaccinated against it.

3. Toxins: e.g., botulinum toxin, produced by the bacterium Clostridium botulinum; lethal at dosesof 1 ng/kg.


The poison from this South American frog is used on arrows

Credit: Corbis


The marine organisms Palythoa

Credit: Corbis


Types ofBiological Warfare Agents


The ricin generated from one castor beanseed can kill a child; eight can kill an adult

Credit: Peter Arnold


Weaponized Anthrax


Outline

• Biological Weapons Programsa. Unit 731 (Japan)

1. The world’s first biological warfare compound, World War II

b. Porton Down (Great Britain)1. Chemical (and later biological) weapons facility

constructed in response to Germany’s chlorine gas attack in World War I


Outline

• Biological Weapons Programs (cont)c. Camp Detrick (U.S.A.)

1. Site of World War II “cloud chamber” experiments on both test animals and human volunteers that demonstrated the viability of biological bombs to spread disease

d. Biopreparat (Soviet Union) 1. A massive effort that encompassed over forty

research and production facilities across the country and led to a deadly outbreak of anthrax following an accidental release of B. anthracis


Timeline of Bioterror Events


Growingmicrobes in the lab takes days

Credit: Courtesy of Julie Millard


New microbetests include handheld devices like this

Credit: Courtesy, Tetracore Inc.


Key Words

• Black powder• High explosives• Harassing agents• Chemical weapons• Lung irritants• Vesicants

• Respiratory poisons

• Nerve agents• Hallucinogens• Herbicides• Biological

weapons• Biological

toxins

Documents

Chemistry and Warfare. The use of "Greek fire" Credit: Bridgeman Art Library