Dichloromethane

What is Dichloromethane CH2C12?

Dichloromethane is an organochloride compound having the chemical formula CH2Cl2. It is a colourless, volatile liquid with a moderately sweet aroma, which is a widely used solvent. Although not miscible with water, it is polar and miscible with several organic solvents. It is also called as Methylene chloride or Methylene dichloride. In general, it can be obtained naturally from macroalgae, oceanic sources, wetlands, and volcanoes. Majority of the Methylene dichloride in the environment is formed due to industrial emissions.

The Methylene chloride is a colourless liquid that has a sweet, penetrating, and gives ether-like smell. It is a volatile liquid chlorinated hydrocarbon and is non-combustible. But if exposed to higher temperatures, it may produce toxic chloride fumes. Vapours are narcotic at higher concentrations. Because of its nature, it is widely used as a paint remover and solvent.

The CH2C12 structure is,

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How is Dichloromethane (CH2C12) Used?

While Dichloromethane CH2C12 is not miscible in water, it can be dissolved in a wide range of organic solvents. These Properties of dichloromethane CH2Cl2 are combined with its volatility, making DCM a highly effective solvent in most of the industrial processes.

DCM is most commonly used as a paint remover. However, it has a wide range of applications and is generally used in aerosol products such as spray paints, insecticides, adhesives, and bathtub refinishing. It is also used to decaffeinate drinks.

So, we can say that, CH2Cl2 soluble in water.


Caffeine Extraction

The Extraction technique is used to separate an organic compound like caffeine, from a mixture of compounds. Solvent-based extractions happen when the caffeine is removed by a chemical solvent, like ethyl acetate or Dichloromethane CH2C12.

Because the caffeine is more soluble in DCM (at 140 mg/ml) than it is in water (at 22 mg/ml), DCM became a preferred solvent to use in the caffeine extraction. In coffee, the unroasted beans repeatedly rinse in Dichloromethane after being steamed. The DCM then extracts the caffeine from them before being drained away. This results in flavoursome coffee beans without the kick.

Because of some health risks associated with the Dichloromethane CH2C12, however, soon it was replaced by non-toxic alternatives. Also, white DCM has various advantages in industrial applications included with its own risks.


Properties of Dichloromethane

Dichloromethane is a colorless solvent with a moderately sweet, chloroform-like aroma. It emits toxic fumes when heated and is highly volatile. Though it forms flammable vapor-air mixtures, it has no definite flashpoint. It is completely miscible with carbon tetrachloride, benzene, ethyl acetate, chloroform, diethyl ether, alcohol, and hexanes. Few of the dichloromethane properties are,

  • Molecular weight: 84.93 g·mol−1;

  • Boiling point of CH2C12: 39.6 °C;

  • Melting point: −96.7 °C;

  • Solubility in water: 17.5 g/L (25 °C);

  • Density: 1.3266 g/cm3;

  • Viscosity: 0.43 cP (20 °C).

Most dichloromethane hazards are connected with human health. Since the substance is extremely toxic, It seriously irritates eyes, throat, nose, and harms the nervous system and can be even fatal. It’s a proven fact that DCM is an animal carcinogen and can cause cancer to humans in case of prolonged exposure.


Production of Dichloromethane (DCM)

The Dichloromethane solvent was first prepared by a French chemist, Henri Victor Regnault, in 1839. He has isolated it from a chlorine and chloromethane mixture by exposing it to sunlight.

Dichloromethane can be synthesized by treating either methane or chloromethane with chlorine gas at temperatures between 400 and 500° C. They undergo a series of reactions that produce more chlorinated products. Approximately 4.00 000 tons were produced in countries such as Japan, Europe, and the United States in 1993.

This method resulted in a combination of chloromethane, chloroform, carbon tetrachloride, and Dichloromethane. They were further isolated by the distillation process.


Dichloromethane CH2C12 Uses

There are a number of uses of CH2C12 to be discussed, and some of them are given here.

Many of the uses of Dichloromethane are associated with its solvent properties. It serves as a part of paint strippers and varnish strippers in the household. In comparison, DCM is also used in the bathtub refinishing.

The chemical is commonly used in industry and manufacturing. It is an important extractive solvent for food production and beverages. For example, the solvent is used to remove caffeine from coffee beans and tea leaves, to make spices, to form hops extract for beers, and more.

This substance is present in lubricating and degreasing products in the transportation industry, to clean the metal parts and surfaces safe and quickly. In addition, DCM is used in the manufacturing of synthetic fabrics, photographic films, inks, and several others.

Furthermore, the Dichloromethane is also used as a solvent in food technology, in aerosol formulations, a solvent in pharmaceutical manufacturing products, can be used as a degreasing agent and also used in the manufacturing of electronics.


Health Hazards

Inhalation

Inhalation of methylene chloride causes irritation in the nose and throat. It impacts the central nervous system (CNS). It is a possible mutagen and is expected to be a human carcinogen.


Carbon Monoxide Poisoning

When dichloromethane has been inhaled and absorbed into the bloodstream, it gives rise to carbon monoxide. This happens because the enzyme Cytochrome P-450 metabolises with DCM, and later the carbon monoxide is formed, and this can lead to carbon monoxide poisoning.

FAQ (Frequently Asked Questions)

1. What to Do When We Are Exposed to Dichloromethane?

Some of the safety steps which need to be taken if we are exposed to dichloromethane are listed below.

Eye Contact

Flush your eyes Immediately with more water for at least 30 minutes. If possible, remove the contact lenses when flushing and seek medical attention at the same time.

Skin Contact

Remove the infected clothing quickly and wash the skin area with large amounts of soap and water. Seek medical attention if you face any irritations.

Inhalation

One should be away from the exposure area and immediately move to an area with fresh air. Seek medical help immediately if any breathing difficulties occur.

2. Which is More Nonpolar, Hexane, or Dichloromethane?

Dichloromethane is more polar, and hexane is more nonpolar.

Hexane is one of the hydrocarbons. Hydrocarbons are nonpolar as carbon and hydrogen are approximately equally efficient at pulling over electrons. The ability to attract electrons to the bond is known as electronegativity. Roughly, carbon and hydrogen have the same electronegativity.

Dichloromethane is polar, as chlorine is electronegative more than the carbon and hydrogen. Therefore chlorine atoms can pull the electrons over, making one side of dichloromethane partially positive and the other side as negative.