Stunning Chloroform (CHCL3): Properties, Synthesis, Reaction and Application

A halogenated organic substance called chloroform is also referred to as trichloromethane. It is a colorless, sweet-smelling volatile liquid. Chloroform has the chemical formula CHCl3 and is made up of the elements carbon, hydrogen, and chlorine. A tetrahedral molecular geometry with C3v symmetry is adopted by the molecule. Due to its distinctive chemical characteristics, it has been widely utilized in numerous applications. Being a chlorinated hydrocarbon, it can go through a variety of chemical processes that involve the chlorine atom.

The American physician Samuel Guthrie produced chloroform for the first time in 1831. In the late 19th and early 20th centuries, it was frequently employed as an anesthetic. It became well-known among medical professionals as an anesthetic for operations and dental procedures. However, due to safety issues and the creation of more potent anesthetics, its use as an anesthetic has drastically decreased over time.

It is formed through the water chlorination process and also released into the air via a variety of manufacturing and usage-related processes. Additional sources of air pollutants include pulp and paper factories, hazardous waste locations, and sanitary landfills. Chloroform is metabolized mostly in the liver within the body. It is transformed into several metabolites, one of which is the highly deadly gas phosgene. One of the factors contributing to chloroform’s possible toxicity and health risks is how the body processes it.

Physical Properties:

  • Boiling Point: CHCl3 boil at 61.2oC.
  • Melting Point: -63.5oC is its melting point. It exists as a liquid at room temperature but can solidify at lower temperatures.
  • Density: Approximately 1.49 g/ml-1.
  • Molecular Weight: The molecular weight is approximately 119.38 g/mol.
  • Solubility: Chloroform is insoluble in water but is miscible with organic solvents, such as ethanol, ether, and benzene.
  • Vapor Pressure: The vapor pressure of chloroform is approximately 200 mmHg at 20 oC.

Chemical Properties:

  • Stability: Although chloroform is a stable substance under typical conditions, it can breakdown in the presence of extreme heat, fire, or ultraviolet (UV) light.
  • Reactivity: Under typical conditions, it is comparatively unreactive. It can, however, go through some chemical processes, such as halogenation processes, in which it combines with halogens like chlorine or bromine to create new compounds.
  • Carcinogenicity: Several regulatory organizations have categorized chloroform as a potential human carcinogen. In particular, for liver and kidney cancer, prolonged exposure to chloroform has been linked to an increased risk of acquiring these diseases.
  • Flammability: Chloroform has a low flash point and is a flammable liquid. It can combine explosively with air, and contact with a lit match, a spark, or other sources of ignition can cause fires or explosions. 
  • Environmental Impact: Chloroform has a negative impact on the environment since it remains there and can contaminate soil, water, and air. Aquatic creatures may suffer detrimental impacts, and it may also contribute to environmental contamination.
  • Solvent characteristics: Chloroform has a wide spectrum of organic compounds that it can dissolve, making it a useful solvent for a variety of laboratory processes and chemical reactions.
  • Toxicity: Chloroform is regarded as poisonous and possibly dangerous to human health. Chloroform vapour exposure or inhalation over an extended period can have negative consequences on the liver, kidneys, and central nervous system.

Synthesis/ Production:

It is crucial to remember that because chloroform is poisonous and potentially dangerous, its synthesis should only be performed by qualified experts in a well-equipped laboratory. The haloform reaction is a reaction that can be used to make chloroform. There are several ways to make CHCl3 besides the haloform process.

Haloform response

A methyl ketone, such as acetone, and a halogen, typically chlorine or bromine, react to produce haloform when they are combined with a strong base, such as sodium hydroxide (NaOH).

3 NaOCl + (CH3)2CO → CHCl3 + 2 NaOH + CH3COONa

  • Chlorine (Cl2), sodium hydroxide (NaOH), and acetone (CH3COCH3) are the three main chemicals needed to create chloroform. Acetone is combined with a sodium hydroxide and water solution in an appropriate reaction vessel. Acetone and sodium hydroxide are commonly mixed in a ratio of 1:1 or 2:1.
  • The reaction mixture is bubbled with chlorine gas. To ensure correct mixing and temperature control, the reaction is typically carried out in controlled environments.
  • Acetone is first oxidized, then chlorine atoms are substituted, and so on, until the reaction is complete. CHCl3 is one of the byproducts produced along with other substances.
  • Following completion of the reaction, the mixture is frequently subjected to separation procedures to separate chloroform. This might entail methods like distillation or extraction to remove impurities and obtain pure chloroform.

Chlorine and methyl chloride reaction:

In industry, chloroform is synthesized by heating chlorine and methyl-chloride. Through the free radical process, at 400-500oC these reactants transfer into more halogenated products.

Cl2 + CH4 → CH3Cl + HCl

Cl2 + CH3Cl → CH2Cl2 + HCl

Cl2 + CH2Cl2 → CHCl3 + HCl

Wurtz-Fittig reaction:

  • A haloformate ester reacts with a Grignard reagent in the Wurtz-Fittig reaction. In this instance, chloroform is produced by treating the haloformate ester with an appropriate Grignard reagent. The response develops as follows.
  • Haloformate ester + Grignard reagent → Chloroform + Magnesium salt

Raschig process:

  • In the Raschig process, calcium hydroxide (lime) and chloromethane (methyl chloride) react in the presence of water. From this process Chloroform and calcium chloride byproducts are produced.
  • Calcium hydroxide + Chloromethane → CHCl3 + Calcium chloride + Water

Chemical reactions:

The presence of the carbon-chlorine bonds in CHCl3 allows it to take part in a variety of chemical processes. Here are a few significant reactions:

1. Dehydrochlorination: In dehydrochlorination reactions, chloroform can transform into various organic compounds. One such is the production of dichlorocarbene in the presence of alcoholic potassium hydroxide (KOH). Dichlorocarbene (CCl2), which is produced, is a highly reactive compound that can take part in further reactions.

CHCl3 + KOH → CCl2 + KCl + H2O

2. Haloform Reaction: In the presence of a potent base, like NaOH, KOH an alcoholic solution, chloroform can undergo a haloform reaction. A haloformate ion (CHCl3O-) and chloride ions (Cl-) are produced during this reaction.

CHCl3 + 3OH- → CHCl3O- + 2Cl- + 2H2O

3. Reduction: It can be reduced to create dichloromethane (CH2Cl2) or to create chloromethane (CH3Cl) or methyl chloride. Different reducing agents, such as metals (like zinc) or reducing agents like lithium aluminium hydride (LiAlH4), can be used to perform these reductions.

4. Metal Reaction: It can form metal alkyls when it reacts with extremely reactive metals like sodium or potassium. To create sodium alkyls in this reaction, chlorine atoms from chloroform are swapped out for sodium atoms.

2CHCl3 + 2Na → 2CHNaCl + NaCl

5. Oxygen Reaction: Under specific circumstances, chloroform can combine with oxygen to create phosgene (COCl2). Usually, a catalyst like copper is included to speed up this reaction.

2CHCl3 + O2 → 2COCl2 + 2HCl

Applications:

Due to its special characteristics, chloroform (CHCl3) has been utilized extensively in a variety of applications. The usage of chloroform has, however, considerably declined over time because of its possible health and environmental risks.

  • Ozone Layer: It does not significantly contribute to the ozone layer’s depletion in the atmosphere. Although it is a pollutant and a part of smog, it is categorized as a volatile organic compound (VOC) and can unintentionally contribute to its creation.
  • Anesthesia: It was once employed as a general anesthetic during operations and other medical procedures. Due to safety concerns, its usage in anesthesia has decreased, and safer alternatives have generally taken its place.
  • Solvent: It is an excellent solvent that may be used to dissolve a variety of materials. It is used as a solvent for waxes, resins, fats, and oils. However, due to safety concerns and the availability of safer alternatives, its use as a solvent has decreased.
  • Extraction: Different chemicals from mixes were extracted using chloroform. The extraction of organic molecules from aqueous solutions or other organic solvents was particularly advantageous.
  • Refrigerant: Due to its low boiling point, It was utilized as a refrigerant in the early stages of refrigeration technology. However, due to safety and environmental concerns, its usage as a refrigerant has been halted.
  • Chloroform, which can control flames, was once utilized in several fire extinguishers. However, because of safety concerns, it has gradually lost use in fire extinguishers.
  • Historical uses: It was also employed in the past for a variety of purposes, including the manufacture of colors, the cleaning of surfaces, the creation of rubber, and in a few household products.
  • Laboratory reagent: It has been used as a reagent in a variety of laboratory operations and reactions. It has been utilized as a solvent for reactions involving delicate chemicals as well as a reactant in organic synthesis.

Safety considerations:

  • To reduce exposure to vapors, chloroform should only be used in properly ventilated spaces with exhaust systems. It shouldn’t be used in small places.
  • Wear the proper personal protection equipment when handling chloroform, such as gloves, safety goggles, a lab coat, or other protective clothes, to avoid coming into contact with skin or breathing in vapors.
  • Keep It away from heat sources and open fires in firmly sealed containers in a cool, well-ventilated environment. To avoid spills and leaks, use suitable storage and handling techniques.
  • Follow local laws and regulations when disposing of chloroform and any waste products that include it. Keep chloroform from being released into the environment.
  • Before using chloroform, perform a thorough risk analysis to find potential dangers, put controls in place, and guarantee the security of the environment and workers.

Conclusion:

In conclusion, chloroform is a chemical substance with a long history of use in medicine and other fields. Its use has been constrained due to safety concerns, even though it contains distinctive chemical properties that make it helpful in some situations. It serves as a reminder of how crucial it is to consider the potential effects on safety and health while working with chemicals.

What effects does chloroform have on biological systems?

Chloroform can influence cellular functions and interact with biological systems. It has been demonstrated to impair ATP synthesis, the cell’s energy currency, and to disturb mitochondrial activity. Various enzymes and proteins involved in biological functions can also be impacted by chloroform.

1 thought on “Stunning Chloroform (CHCL3): Properties, Synthesis, Reaction and Application”

Leave a comment