Phosgene
Phosgene is a highly toxic, colorless gas with the formula COCl₂. It is used to manufacture chemicals and was deployed as a chemical warfare agent.
Hydrolysis: A chemical reaction in which a compound is cleaved by water. Moisture in respiratory tissue reacts with phosgene and contributes to corrosive lung injury.
Isocyanate: An organic functional group containing the sequence –N=C=O. Phosgene is widely used to produce isocyanates for polymers and other materials.
John Davy: An English chemist who discovered phosgene in 1812 by exposing a mixture of carbon monoxide and chlorine to sunlight. His photochemical preparation gave the gas its name, derived from Greek words for light and birth.
Phosgene poisoning: Illness caused by inhaling phosgene, ranging from airway irritation to fatal lung injury. This clinical condition is the direct human consequence of phosgene exposure.
Carbon dioxide: A colorless gas with the formula CO₂, produced by respiration and combustion and used in many industries. Both contain carbon and oxygen, but phosgene also contains chlorine and is acutely toxic.
Pulmonary edema: A buildup of fluid in the lungs that impairs gas exchange. Phosgene exposure can cause delayed fluid accumulation that makes breathing progressively harder.
Polyurethane: A polymer containing urethane linkages, used in foams, coatings, adhesives, and elastomers. Industrial phosgene-derived isocyanates are major starting materials for many polyurethanes.
Chemical warfare in World War I: The use of toxic chemicals as weapons during the First World War. Phosgene became one of the war’s deadliest chemical agents, often used in combination with chlorine.
Latent period: An interval between exposure to a harmful agent and the appearance of symptoms. Phosgene poisoning can worsen after a symptom-free interval, delaying recognition of severe injury.
Carbon monoxide: A colorless, odorless gas with the formula CO that interferes with oxygen transport in blood. Its formula resembles phosgene’s carbon–oxygen core, but its toxic mechanism and composition differ.