Carbon Tetrachloride/CCl4: A Complete Amazing Overview

Carbon tetrachloride (CCl4), often known as Tetrachloromethane, is a liquid that is a member of the chlorinated hydrocarbon family. CCl4 is a colorless, clear, and flammable liquid with a sweet smell (an ether-like odor). In the past, carbon tetrachloride has been employed as a solvent in a variety of industrial applications, but because of environmental and health risks, its use has substantially decreased.

Carbon tetrachloride is composed of one carbon atom and four chlorine atoms, arranged in a tetrahedral shape. The viscous liquid can dissolve in a variety of organic solvents but does not mix well with water. Due to its distinct chemical characteristics and diverse variety of historical applications, CCl4 has become the subject of recent research. Previously, carbon tetrachloride was frequently employed as a solvent for oils, fats, and waxes as well as a cleaning agent. Additionally, it was employed as a refrigerant and in fire extinguishers. However, as we learned more about its harmful effects, its use was restricted and replaced with safer alternatives.

The poisonous nature of carbon tetrachloride and its negative impact on living things have led to a decline in its use in recent years. It poses significant health dangers to both humans and animals, as it has been found to be a powerful liver toxin and a recognized carcinogen. As a result, it is mostly restricted to certain laboratory applications under strict safety regulations and is no longer employed in the majority of industrial procedures.

Properties of Carbon Tetrachloride:

  1. Density: Its density is around 1.586 g/cm³.
  2. Melting Point: It has a melting point of -22.9°C.
  3. Boiling Point: The boiling point is approximately 76.7°C.
  4. Stability: Although it is generally stable under normal circumstances, it can react with some compounds like metals, alkaline solutions, and powerful reducing agents.
  5. Inertness: Carbon tetrachloride can slowly break down in the presence of heat or light, releasing poisonous gases like phosgene and chlorine gas.
  6. Combustibility: It does not support combustion and is not flammable.
  7. Polarizability: The high polarizability of the substance makes it a potent solvent for dissolving non-polar substances.
  8. Solubility: It dissolves in many organic solvents like chloroform, benzene, and others. It is also slightly soluble in water.

Synthesis/ Production:

There are numerous processes that can be used to create CCl4, each of which involves a unique chemical reaction. Its production and use are heavily restricted in many nations due to the health and environmental dangers associated with it. The following are some of the primary procedures for creating carbon tetrachloride.

Direct Chlorination of Methane:

Methane (CH4) can be directly chlorinated in the presence of chlorine gas (Cl2) and ultraviolet (UV) light to produce carbon tetrachloride. The major product of this process is created by a sequence of reactions.

  • Reactants preparation: The first step is to make sure that the methane and chlorine gas reactants are properly prepared. Natural gas known as methane can be created chemically or obtained from fossil sources. Normally, sodium chloride solution (brine) electrolysis or other chlorination processes are used to produce chlorine gas.
  • Reaction: Ultraviolet (UV) light serves as a catalyst for the direct chlorination of methane. UV light provides the necessary energy for the reaction to occur. In this process, one methane molecule interacts with four chlorine gas molecules to create one carbon tetrachloride molecule and four hydrogen chloride (HCl) molecules as byproducts.              

CH4 + 4Cl2 → CCl4 + 4HCl

  • Separation and Purification: After the reaction, the mixture still contains unreacted chlorine and methane as well as carbon tetrachloride and hydrogen chloride. To obtain pure carbon tetrachloride, the products are separated and purified using a variety of methods, including fractional distillation.
  • Safety Considerations: It’s crucial to remember that the technique of producing carbon tetrachloride by directly chlorinating methane is risky. Chlorine gas is poisonous and can irritate the skin and respiratory system. Furthermore, if consumed, swallowed, or absorbed through the skin, it will be extremely poisonous and poses serious health hazards. Additionally, due to ozone depleting properties, it has been phased out of numerous industrial and commercial applications.

Chlorination of Carbon Disulfide:

  • Chlorination of carbon disulfide is possible, but the process is more complex than it is for methane. Carbon tetrachloride is primarily created using alternative techniques, like the direct chlorination of methane, due to the difficult and less practical nature of this procedure. 
  • Instead of carbon tetrachloride, the reaction’s main product is thionyl chloride (SOCl2). In this process, one carbon disulfide molecule interacts with three chlorine gas molecules to create one thionyl chloride and one sulphur dichloride (S2Cl2) molecule.

CS2 + 3Cl2 → SOCl2 + S2Cl2

  • To convert thionyl chloride to carbon tetrachloride, further chemical steps and purification processes would be required, making the overall process more complex and less efficient.

Halogen Exchange:

  • The carbon tetrachloride is created via the halogen exchange method through a sequence of reactions involving other halogenated chemicals. Due to its complex nature and the availability of simpler and more effective synthesis pathways, this methodology is not frequently utilized.
  • Essentially, this process involves treating chloroform (CHCl3) with chlorine gas to create carbon tetrachloride and hydrogen chloride (HCl).

CHCl3 + Cl2 → CCl4 + HCl

Chemical Reactions:

Due to its toxicity and environmental risks, carbon tetrachloride must be handled with the utmost care. However, it can participate in the following chemical processes.

Halogenation Reactions: Iodine (I2) and bromine (Br2) are two halogens that can halogenate carbon tetrachloride.

CCl4 + Br2 → CCl3Br + BrCl

Dehydrohalogenation: The processes on CCl4 can remove hydrogen chloride (HCl) and create dichlorocarbene (CCl2). Strong bases, such as sodium or potassium hydroxide, are necessary for this reaction.

CCl4 + 2KOH → CCl2 + 2KCl + 2H2O

Free Radical Reactions: Free radical reactions using CCl4 can be started by heat or light. Free radicals produced as a result can take part in other chain reactions.

CCl4 → CCl3 + Cl

Substitution Reactions: With other substances, carbon tetrachloride can engage in substitution processes. An illustration of this reaction is the formation of chloroform (CHCl3) and ammonium chloride (NH4Cl) from ammonia (NH3).

CCl4 + 3NH3 → CHCl3 + 3NH4Cl

Ozonolysis: Carbon tetrachloride can react with ozone (O3) to form phosgene (COCl2) and oxygen (O2):

CCl4 + 3O3 → COCl2 + 3O2

Applications:

Due to its special characteristics, carbon tetrachloride (CCl4) was previously widely employed in a variety of applications. However, because of its harmful influence on the environment and humans, its usage has considerably decreased and has even been outlawed or limited in many countries. Safer substitutes have been adopted as a result in numerous industrial and commercial applications.

  1. History of Anesthesia: The general anesthetic carbon tetrachloride was first utilized in the early 20th century. However, due to its liver toxicity and the invention of safer anesthetics, its use was abandoned.
  2. Solvent: It was employed as a solvent for a variety of organic substances, particularly fats, oils, resins, and rubber. Additionally, it was utilized to clean industrial and electrical equipment.
  3. Fire Extinguisher: Historically, carbon tetrachloride was utilized in fire extinguishers due to its non-flammability and capacity to remove oxygen from the fire. However, because it emits poisonous gases when exposed to high heat, it has been phased out.
  4. Refrigerant: In the early 20th century, cooling systems used carbon tetrachloride as a refrigerant. However, due to its toxicity, safer substitutes were later used in its place.
  5. Pesticide: In agricultural settings, carbon tetrachloride was employed as a pesticide to control worms and insects. However, it was no longer used as a pesticide due to its toxicity to both pests and humans.
  6. Chemical intermediary: Chlorofluorocarbons (CFCs), which were employed as propellants and refrigerants in aerosol cans, were produced using carbon tetrachloride as an intermediary. However, it was discovered that CFCs reduced the ozone layer, which caused both CFCs and carbon tetrachloride to be phased out.

Conclusion:

Despite the fact that carbon tetrachloride once played a key role in a number of industries, its decline and restricted use are now due to its health and environmental risks. In order to put protective measures in place to guard against its negative impacts on the environment and living things, it has been essential to understand how it affects the ozone layer and human health.

How does CCl4 help in ozone depletion?

One of the main causes of the ozone hole in the atmosphere is carbon tetrachloride. It can degrade and release chlorine atoms into the atmosphere, which can subsequently catalytically destroy ozone molecules in the stratosphere. In order to safeguard the ozone layer, the Montreal Protocol has to established limits on the manufacture and use of carbon tetrachloride.

Is CCl4 toxic?

Both people and animals are extremely poisonous to carbon tetrachloride. It is metabolized largely in the liver, where it can seriously harm liver cells and result in liver failure. The kidneys, central nervous system, and respiratory system can all be impacted by prolonged exposure of it. According to studies, it may cause cancer. In animals, prolonged exposure to high concentrations of the substance has been linked to an increased risk of liver cancer. As a persistent environmental contaminant, carbon tetrachloride can pollute soil, water, and air. It can also bioaccumulate in the food chain and threaten aquatic life.

3 thoughts on “Carbon Tetrachloride/CCl4: A Complete Amazing Overview”

  1. Its like you read my mind You appear to know a lot about this like you wrote the book in it or something I think that you could do with some pics to drive the message home a little bit but instead of that this is fantastic blog An excellent read I will certainly be back

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