Chloroform
Chloroform, or trichloromethane, is a colorless and volatile liquid known for its sweet smell reminiscent of ether, with the chemical formula CHCl₃. Historically, chloroform was used as an anesthetic in medical settings, including during significant historical events like the Mexican-American War. However, due to health risks and a higher incidence of fatalities associated with its use compared to ether, it fell out of favor in medical practices by the late 19th century. Today, chloroform is primarily utilized as a solvent in laboratories and various industrial applications, such as in the production of refrigerants and propellants.
Despite its utility, chloroform poses serious health risks. Exposure, which can occur through inhalation or skin contact, can lead to dizziness, nausea, and in severe cases, damage to vital organs like the kidneys and liver. Additionally, prolonged exposure is a concern, as chloroform is considered a potential carcinogen and teratogen. Although trace amounts may be present in chlorinated water, the levels are typically not harmful. Safety concerns have led to a decline in its use across many industrial applications, with alternatives being sought to mitigate risks associated with this chemical.
Chloroform
Chloroform, which is also called trichloromethane, has the chemical formula CHCl3. It is a colorless, volatile liquid that has a sweet smell similar to ether. It was once commonly used as an anesthetic in the United States and other countries; however, chloroform's potential health risks made it less popular in medicine by the 1870s. Today, chloroform is commonly used as a solvent in laboratories and in industry, specifically in refrigeration. This chemical can cause a number of adverse health reactions and might also be a carcinogen.
Chemical Properties of Chloroform
Chloroform is a nonflammable, volatile liquid. It is colorless but has a sweet smell similar to ether. Chloroform is a compound, and its chemical structure is CHCl3; it is made up of one carbon atom, one hydrogen atom, and three chlorine atoms. Its melting point is about 64° C, and its boiling point is about 62° C. Although the liquid is not flammable, fire can cause bottles of liquid chloroform to explode. Chloroform is slightly soluble in water but reacts strongly with chemically active metals, such as lithium, potassium, and sodium, and some other chemicals. Because of the potential for these strong reactions, chloroform poses a fire hazard even though it is not flammable.
Chloroform is produced mostly for lab and industrial use and can be released into the atmosphere when it is used by industry. For example, it can form and be released when drinking water and wastewater are chlorinated. It can also be released in landfills, hazardous waste sites, paper factories, and other sites. Although chloroform used to be medically administered to humans, chronic exposure can cause serious health problems.
Discovery and Early Use of Chloroform
Soon after chloroform was discovered around 1831, scientists found that it had anesthetic effects on humans. Before the 1800s, people used opium and alcohol to reduce pain during medical procedures. In the early 1800s, however, medical professionals started using ether as an anesthetic. After ether became popular in medical procedures, scientists began using chloroform in a similar way.
Chloroform was usually administered by putting drops on a sponge and having the patient inhale the fumes. Chloroform became extremely popular in medicine during the early 1800s. The compound was even used during the Mexican-American War to treat soldiers wounded in battle. Chloroform was still being used at the time of the American Civil War to reduce pain during medical procedures such as amputations.
Soon after chloroform became a preferred anesthesia, deaths began to increase because of its use, in part because the dosages for chloroform were lower than the dosages for ether. If doctors administered as much chloroform as they would ether, they could induce cardiac arrest or respiratory problems in their patients. By the 1870s, scientists had found that many more deaths occurred from chloroform anesthesia than from ether anesthesia. Because of this, chloroform started to become less popular. By the late 1800s, it was replaced almost entirely by ether in medical procedures. However, chloroform was still occasionally used in medical procedures.
Modern Uses of Chloroform
Chloroform is used in a number of different modern applications. It is a solvent and is often used in laboratories. In the past, it was used in industry to extract fats, oils, waxes, and other materials. It was also used to help extract and purify medications, vitamins, and flavorings. It was even used in other industrial applications, such as dry cleaning and spot removal. Because of safety concerns, however, the compound is no longer used in many of these industrial applications. Today in the United States, the compound is mostly used to make propellants and refrigerants.
Effects on Human Health
Chloroform is no longer used in medicine because of its potential health risks. Chloroform is most often ingested through the skin or by inhalation, but it can also be ingested by mouth. A lethal oral dose of chloroform can be as little as 10 milliliters. Skin exposure to the liquid can cause a rash or burning. Eye exposure can cause burns and other damage. Although chloroform can have many different effects on the body, exposure is not easily traced because chloroform is quickly eliminated from the body.
In low doses, chloroform can cause dizziness, lightheadedness, nausea, and confusion. In larger doses, chloroform can be used as an anesthesia. It can also cause changes in heartbeat, reduced respiratory function, and nausea and vomiting. Prolonged exposure to chloroform can damage the kidneys and liver. It is likely that chloroform is a carcinogen (carcinogens cause cancer) and a teratogenic (teratogenic can cause birth defects). Also, storing chloroform for long periods can pose health problems. Chloroform can oxidize into phosgene, which has a chemical name of COCl2. Phosgene was used as a chemical weapon in the past. Preservatives can be added to chloroform to ensure that it does not oxidize.
Chloroform can also negatively affect the central nervous system, causing depression. Because of this, chloroform has been labeled a toxic substance. Today, most chloroform exposure occurs by accidental exposure in industrial workplaces. It is being replaced by other solvents in some of its industrial applications. The general public can be exposed to trace amounts of chloroform by drinking or swimming in chlorinated water, but these minute exposures are not likely to cause harm.
Bibliography
"Chloroform." EPA. United States Environmental Protection Agency. Jan. 2000. Web. 17 Nov. 2015. <http://www3.epa.gov/airtoxics/hlthef/chlorofo.html>
"Ether and Chloroform." History.com. A&E Television Networks, LLC. 2010. Web. 17 Nov. 2015.
<http://www.history.com/topics/ether-and-chloroform>
Senthilingam, Meera. "Chemistry in Its Element - Chloroform." Royal Society of Chemistry. Royal Society of Chemistry. Web. 17 Nov. 2015. <http://www.rsc.org/chemistryworld/podcast/CIIEcompounds/transcripts/chloroform.asp>
"Chloroform (Trichloromethane)." Department of the Environment: National Pollutant Inventory. Commonwealth of Australia. Web. 17 Nov. 2015. <http://www.npi.gov.au/resource/chloroform-trichloromethane>