مقاله ها
?Chloroform, What is it and What are its Uses
Chloroform is a chemical substance found in nature and is also produced artificially. The biggest reason everyone knows chloroform is that it has been used for anesthesia throughout history. Although chloroform is not used for this purpose today, it still holds a place in our memory.
Chloroform, also known as trichloromethane and methyl trichloride, is a chemical compound with the formula CHCl3. This compound is a colorless and volatile liquid at room temperature, but it is not flammable.
This chemical compound is a highly effective solvent for various organic compounds used in scientific research and industrial processes. The article in KHC Dental provides further details on this, please join us.
?What is Chloroform
Chloroform is a natural organic compound found in the air and coastal waters, lakes, and groundwater. However, most of the trichloromethane present in the environment is produced by humans. Higher levels of this chemical are found in industrial areas and the air above swimming pools where the water is disinfected with chlorine.
Chloroform is a liquid with a sweet smell, similar to ether, and is 40 times sweeter than sugar in taste. Some people compare its smell to that of disinfectants, similar to the scent experienced in hospitals and treatment centers. Chemists describe the odor of chloroform as vaguely resembling that of acetone.
This compound is used as a solvent for extracting fats, oils, greases, rubber, wax, resin, lacquer, producing synthetic silk, gum, and adhesives. It is also used as an industrial solvent in the extraction and purification of certain antibiotics, alkaloids, vitamins, and flavorings.
This substance is also used as a solvent in organic chemistry, photography, and in the manufacture of paints, medicines, and pesticides. Its other applications include stain removal in dry cleaning, as a fumigant, and in fire extinguishers to reduce the freezing point of carbon tetrachloride.
Chloroform formulated with other substances is used to control roundworms in animals. This compound is being continuously replaced with less toxic solvents and may no longer be used in some of these applications. Its use as an inhalation anesthetic during surgery has also largely ceased.
History of the Discovery of Chloroform
Moldenhauer, a German pharmacist, was the first to synthesize chloroform in 1830. Although he mistakenly named it chloric ether. His method involved combining chlorinated lime or calcium hypochlorite with ethanol. After experiments by Justus von Liebig and Eugene Soubeiran, this chemical compound was identified in 1834. The French chemist Jean-Baptiste Dumas discovered its empirical formula and named it chloroform. The potent effect of this compound as an anesthetic was demonstrated in 1842 by Robert Mortimer Glover through experiments on laboratory animals. James Simpson was the first person to use this compound on humans during surgery in 1847, which led to chloroform being recognized as the best anesthetic in the world.
Formula and Chemical Structure of Chloroform
Chloroform is a relatively simple organic compound with the formula CHCl3, consisting of a central
carbon atom along with three chlorine atoms and one hydrogen atom. In the chloroform molecule, the repulsive forces between the hydrogen and chlorine atoms shape this molecule into a perfect quadrilateral. These forces push the surrounding atoms as far apart as possible, leading to geometric symmetry and specific angles in the molecule. The covalent bonds within this molecule make it slightly polar, which causes chloroform to dissolve in water. The structure of a molecule determines how it reacts with other chemical substances and how it interacts with biological functions such as neurotransmitters. Organic compounds that include two or more halogen atoms are generally known as polyhalogenated compounds. The high reactivity of these compounds has made them a very important category of chemical materials. Chloroform also falls into this category of compounds. Despite evidence that these compounds have negative impacts on the environment and human health, industries continue to use them due to their numerous applications and high diversity of uses.
Chemical and Physical Properties of Chloroform
Appearance and physical characteristics: colorless liquid
Molecular weight: 119.38 grams per mole
Melting point: -63.41 degrees Celsius (-82.14 degrees Fahrenheit)
Boiling point: 61.17 degrees Celsius (142.1 degrees Fahrenheit)
Solubility: slightly soluble in water, and well soluble in ethyl alcohol, ether, acetone, benzene, and other organic solvents
Flash point: 60.5-61.5 degrees Celsius
Storage temperature: 2-8 degrees Celsius
?What are the Applications of Chloroform
Chloroform is used as a solvent for iodine, alkaloids, fats, and some other substances. This compound is mainly used in the production of the refrigerant Freon R-22. The use of R-22 as a refrigerant in developed countries has been discontinued due to issues related to global warming, but it still has a high demand in developing countries due to its ease of access and production.
Once the effects of this compound were identified, it was used as an important anesthetic in medical surgeries. Even some criminals use it to incapacitate their victims.
It is said that inhaling air containing 900 ppm of chloroform can lead to dizziness, headaches, and fatigue. With the discovery of the toxicity of this compound and its harmful effects on the liver, kidneys, and central nervous system, its use as an anesthetic was replaced by safer products.
The toxicity of this substance is attributed to phosgene. The oxidation of chloroform under light can produce a highly toxic gas known as phosgene. For this reason, chloroform is stored in dark bottles with narrow openings that are completely full to prevent any contact with air.
?What Is the Application of Chloroform In Dentistry
Dental chloroform is one of the materials used for local anesthesia in root canal treatment and tooth nerve extraction.
Production of Chloroform
This compound is produced by heating a mixture of chlorine and methane. At temperatures of 400-500 degrees Celsius, halogenation occurs through a radical chain reaction, leading to the conversion of methane or chloromethane into chlorinated compounds.
CH 4 + Cl 2 → CH 3 Cl + HCl
CH 3 Cl + Cl 2 → CH 2 Cl 2 + HCl
CH 2 Cl 2 + Cl 2 → CHCl 3 + HCl
When chloroform is exposed to more chlorine, it is converted to carbon tetrachloride.
CHCl₃ + Cl₂ → CCl₄ + HCl
The output of this process includes a mixture of four substances: chloromethane, dichloromethane, chloroform (trichloromethane), and carbon tetrachloride, which are separated by distillation.
The first industrial method for producing this chemical compound is the reaction of acetone (or ethanol) with sodium hypochlorite or calcium hypochlorite, known as the halo-form reaction. Chloroform can be isolated using acetate salts or formate salts produced from the starting ethanol through distillation. This reaction is still used to produce bromoform and iodoform. The halo-form method for producing regular chloroform is no longer updated or used, but it is utilized for producing dual materials in the industry.
Deuterochloroform is obtained from the reaction of sodium deuteroxide with hydrate chloride, and a small amount of aldehyde hydrogen remains in the product. Samples with higher isotopic purity than trichloroacetophenone are extracted as the starting material.
Accidental Synthesis of Chloroform
Halo-form reactions may also occur unintentionally even in closed environments. For example, the combination of sodium hypochlorite solution (bleach) with methyl ethyl ketone (nail polish remover) leads to the production of chloroform. Additionally, the combination of pool chlorine and acetone has the same effect.
How to Use Chloroform
This compound was previously used as a powerful anesthetic in surgeries. When inhaled or ingested, this compound has anti-anxiety, euphoric, and sedative effects. However, after the toxic damage it causes to the body was identified, the use of trichloromethane as an anesthetic was discontinued. The health risks associated with this compound include damage to the kidneys, liver, and nerves. In industries, trichloromethane is still recognized as a widely used compound with two main applications.
One of the most important industrial applications of it is its use as a solvent in the production of pesticides. This compound is useful for extracting medicinal alkaloids (such as morphine) from plant materials (such as poppy). Trichloromethane is also known as a good reagent, as it is a source of dichloromethane. In this process, sodium hydroxide is used together with chloroform and with the help of a catalyst to produce dichloromethane. This compound also helps in the production of many precursor chemicals.
Furthermore, trichloromethane is used industrially on a large scale as a precursor to polytetrafluoroethylene (PTFE) which has diverse applications. This compound is used as a coating and lining for pipes and corrosion-resistant equipment, and is also known as a precursor to various refrigerants that play an important role in air conditioning systems.
Side Effects and Dangers Associated with Contact with Chloroform
As expected, inhalation of chloroform vapor as an anesthetic has a suppressive effect on the activity of the central nervous system. Breathing about 900 parts of chloroform per million parts of air (900 ppm) for a short time can cause dizziness, fatigue, and headache.
Chronic exposure to chloroform may damage the liver (the site of chloroform metabolism to phosgene) and kidneys, and some people develop sores upon skin contact with this chemical. About 10% of people show an allergic reaction to this substance, which may lead to a fever of around 40 degrees Celsius (104 degrees Fahrenheit).
Animal studies have shown that abortion occurs in mice that have inhaled air containing 30 to 300 ppm chloroform during pregnancy, and also in mice that have consumed chloroform during pregnancy.
The offspring of mice and mice that were exposed to chloroform inhalation during pregnancy are more prone to congenital defects, and abnormal sperm have been observed in male mice that have inhaled air containing 400 ppm chloroform for several days. The effect of chloroform on human reproduction is still unknown.
Chloroform was used in toothpaste, cough syrups, ointments, and other drugs before 1976, but since then it has been prohibited in consumer products in the United States. The 11th NTP report on carcinogens indicates that this substance can reasonably be anticipated to be carcinogenic to humans and is associated with hepatocellular carcinoma. During work, reasonable precaution to reduce unnecessary exposure is prudent.
The use of safer alternatives, such as dichloromethane, has led to a significant reduction in its use as a solvent.
Chloroform Hazards to Health
The effect of this chemical compound on health depends on the dose consumed. At low doses, it may cause fatigue, but with increasing dose, the person will quickly lose consciousness and will not feel any pain or sensation. At higher doses, there is a risk of respiratory problems, complete muscle relaxation, and paralysis of the chest muscles, which may be fatal.
The effects of chloroform on the human body are to some extent dependent on the dose and method of use. According to the Wisconsin Department of Health, exposure to 100 ppm of this chemical can immediately or in a short time cause fatigue, dizziness, and headache. Trichloromethane is known for its anesthetic property. If used in small doses, it can numb or anesthetize a person, while at high concentrations it can be lethal.
There is evidence that this compound, in addition to affecting the liver and kidneys, directly affects the central nervous system and at high doses can lead to respiratory problems and coma. Although many of us know this compound as an anesthetic, its effects on the human body are much more complex and, if not carefully controlled, can be lethal.
Methods for Identification and Detection of Chloroform
Physical properties
The first method that can be used to identify this chemical compound is to examine its physical properties such as its strong odor and freezing point. However, this method is not very accurate as it may resemble other chemical substances in appearance. For example, its odor is very close to that of ether, which is another colorless and volatile chemical.
Chemical analysis
The best method for identifying chloroform is chemical analysis. This compound can be identified using chemical test kits in the laboratory or through sampling. This method is particularly effective in the detection of trichloromethane in the environment, which is important for ecological studies and wildlife conservation. Additionally, as a toxic substance with numerous criminal applications, chloroform toxicology tests are of great importance for forensic medical investigations.
The Fate of Chloroform in the Ecosystem
Chloroform is produced naturally and industrially. In fact, about 660,000 tons of this substance are produced annually, 90% of which is supplied from natural sources. These natural sources include several types of seaweed, fungi, and abiotic natural processes in the soil.
This compound evaporates easily and decomposes into other compounds in the gaseous state. The compounds produced as a result of the decomposition of chloroform include the following:
- Phosgene
- Dichloromethane
- Formulation Chloride
- Carbon Monoxide
- Carbon dioxide
- Hydrogen chloride
The degree of destruction of this chemical compound depends on its release location. Its lifetime in the atmosphere varies between 55 and 620 days. Additionally, its biological degradation in water can range from 1.5 days to over 1000 years, depending on the depth and aerobic or anaerobic conditions. However, fortunately, trichloromethane does not accumulate, which minimizes its environmental impact.
?What Role does Chloroform Play in Human Life
It may seem a bit strange that a substance so intertwined with human life can be very harmful to health. Although it has not been used for anesthesia for a long time, the negative impacts of drugs currently used for this purpose are much less harmful to human health than trichloromethane.
Nevertheless, chloroform is still actively used in the chemical industry. It is believed that in the near future we will rid ourselves of all chemicals that harm nature and people, especially trichloromethane.
Unfortunately, our waters are quickly becoming contaminated as local municipalities around the world use it. The chlorination process of drinking water is still ongoing, and there is a high likelihood that the organic substances present in water and chlorine will combine to form dangerous components like chloroform. There is currently no other solution to this issue. However, we hope that this problem will also be resolved in the near future.
Side Effects of Oral Consumption of Chloroform
If ingested, this compound is converted into a chemical called phosgene. Phosgene is toxic to cells, so overuse of it can cause cell death. If you look at how this compound is used in movies and television, you might think that it is a harmless chemical compound, but this is completely wrong.
Some studies have shown a possible association between the intake of trichloromethane in water and the incidence of colorectal and bladder cancer. In research experiments, liver and kidney cancer was observed in rats and mice who ate chlorine-containing food for long periods of time or consumed chloroform-containing water in large quantities.
Regarding the anesthetic property of trichloromethane, if the inappropriate dose is administered or if a cloth soaked in chloroform is placed too tightly on the face, it can be very dangerous and cause chloroform.
Precautions In Case of Exposure to Chloroform
The first thing you need to do is to get away from the contact source as soon as possible. If the person is unconscious and unable to move, you should move them away immediately.
If the clothes are contaminated, change them immediately and quickly wash the area with plenty of water if the eyes and skin come into contact.
Severe or irreversible side effects of trichloromethane leading to subsequent complications include nephrotoxicity, cardiac arrhythmias, liver toxicity, hypotension, liver toxicity, decreased cardiac output.
The symptomatic side effects that develop are more or less tolerable and can be treated symptomatically if they become severe, including burning, skin and mucous membrane burns, and blisters.
Dangers of Working with Chloroform
It is mixed with alcohol, benzene, petroleum ether, carbon tetrachloride, carbon disulfide, and oils. It reacts strongly with strong caustic substances, strong oxidizers, chemically active metals such as aluminum, lithium, magnesium, sodium or potassium and acetone, causing fires and explosions.
This compound can attack plastics, rubber, and coatings. Trichloromethane decomposes slowly under the influence of light and air. It also decomposes in contact with hot surfaces, flames, or fire, forming caustic and toxic gases composed of hydrogen chloride, phosgene, and chlorine.
During long-term storage, dangerous amounts of phosgene accumulate in the presence of oxygen and ultraviolet radiation. To prevent accidents, commercial compounds must be stabilized with ethanol or amylene, but samples that have been recovered or dried no longer have any stabilizers and should be treated with caution. Suspicious bottles should be tested for phosgene.
The Price of Buying and Selling Chloroform
Chloroform has a different price in terms of the manufacturer’s brand and quality, and you can get it at the best price and quality from Rojan Behdasht Mandegar Dental Equipment Manufacturing Company for various applications.
