Definition and Usage Areas of Dichloromethane

Dichloromethane (DCM or methylene chloride) is an organic compound with the formula CH2Cl2. This colorless, volatile liquid with a moderately sweet aroma is commonly used as a solvent. While not miscible with water, it is miscible with many organic solvents. One of the most well-known applications of dichloromethane is the drinking bird heat engine.

Natural sources of dichloromethane include ocean springs, macroalgae, wetlands, and volcanoes. However, the majority of dichloromethane in the environment is a result of industrial emissions.

DCM is produced by treating either chloromethane or methane with chlorine gas at 400-500°C. At these temperatures, both methane and chloromethane undergo a series of reactions that produce increasingly chlorinated products. In this way, approximately 400,000 tons were produced in 1993 in the USA, Europe and Japan.

CH4 + Cl2 → CH3Cl + HCl

CH3Cl + Cl2 → CH2Cl2 + HCl

CH2Cl2 + Cl2 → CHCl3 + HCl

CHCl3 + Cl2 → CCl4 + HCl

The production of these processes is a mixture of chloromethane, dichloromethane, chloroform and carbon tetrachloride. These compounds are separated by distillation.

DCM was first prepared in 1839 by the French chemist Henri Victor Regnault (1810-1878), and a mixture of chloromethane and chlorine was isolated from exposure to sunlight.

Usage areas

• It is widely used as paint stripper and degreaser.
• It has been used in the food industry to decaffeinate coffee and chocolate, as well as to prepare hop extracts and other flavorings.
• Its volatility has resulted in its use as an aerosol spray propellant and as a blowing agent for polyurethane foams.
• The low boiling point of the chemical compound allows the chemical to run in a heat engine that can extract mechanical energy from small temperature differences. An example of a DCM heat engine is the drinking bird. The toy works at room temperature.
• DCM chemically joins some plastics by welding. For example, it is used to cover the housing of electricity meters. Often sold as the main component of plastic welding adhesives, it is also widely used by model maker hobbyists to assemble with plastic components. It is often referred to as “Di-clo”.
• It is used in the garment printing industry to remove heat-sealed garment transfers and takes advantage of volatility innovation elements: bubble lights and jukebox displays.
• DCM is used in civil engineering materials testing; It is used to allow testing of materials by separating the binder from an asphalt or macadam aggregate, especially when testing bituminous materials as a solvent.