Dichloromethane

Description

Dichloromethane is a colorless liquid with an ethereal, but penetrating odor. Its miscibility in alcohol and ether and slight solubility in water has made it an ideal solvent and otherwise extremely versatile chemical. It has been used industrially (solvent and paint remover), as a drug (inhalation anesthetic) and as an agricultural chemical (growth regulator and fertilizer). It is narcotic in high concentrations and carcinogenic. Inhalation exposure to this substance irritates the nose and throat and affects the central nervous system.

Description

March is MOTW Solvent Month! This is the first of four articles about key solvents — Ed.
Dichloromethane, commonly called methylene chloride, is a solvent that is widely used in chemical research and manufacturing. It is a highly volatile liquid (see fast facts table), but it is neither flammable nor explosive in air.
Dichloromethane is commonly produced by chlorinating methane. The process also produces the other three C1 chlorohydrocarbons—chloromethane, trichloromethane (chloroform), and tetrachloromethane (carbon tetrachloride). The four are separated via distillation.
Although dichloromethane is the least toxic C1 chlorohydrocarbon, it does present hazards. Inhaling it can produce symptoms ranging from drowsiness to respiratory tract irritation and even death. It also may be carcinogenic, but not enough studies have been done to establish the degree of exposure that causes cancer.
Despite its health risks, dichloromethane is one of the main solvents used to decaffeinate coffee beans. After the caffeine is removed, the solvent’s volatility makes it easy to remove residual solvent. Any remaining dichloromethane is well below the 10-ppm concentration allowed by the US Food and Drug Administration.

The Uses of Dichloromethane

Methylene chloride is used principally as a solvent in paint removers. It is also used as an aerosol propellant, processing solvent in the manufacture of steroids, antibiotics, vitamins, and tablet coatings; as a degreasing agent; in electronics manufacturing; and as a urethane foamblowing agent.Methylene chloride is also used in metal cleaning, as a solvent in the production of polycarbonate resins and triacetate fibers, in film processing, ininkformulations, and as anextraction solvent for spice oleoresins, caffeine, and hops. It was once registered for use in the United States as an insecticide for commodity fumigation of strawberries, citrus fruits, and a variety of grains.
Methylene chloride has been used as a blowing agent for foams and as a solvent for many applications, including coating photographic films, pharmaceuticals, aerosol formulations, and to a large extent in paint stripping formulations. It is used as a solvent in a number of extraction processes, where its high volatility is desirable. It has high solvent power for cellulose esters, fats, oils, resins, and rubber, and is more water soluble than most other chlorinated solvents. Formulations for paint stripping may contain other solvents as well as methylene chloride and are frequently found outside the workplace. These formulations often contain other ingredients that retard evaporation and in the process increase the likelihood of skin irritation.
Dichloromethane was used as an anesthetic gas but is no longer used because of the narrow therapeutic index.

The Uses of Dichloromethane

To a solution of the SM (300 mg, 2.30 mmol) in DCM (6 mL) at 0 C was added TEA (0.64 mL, 4.6 mmol) followed by MeSO2Cl (0.21 mL, 2.76 mmol). The reaction mixture was stirred at 0 C for 30 min, then was allowed to warm to RT over 2 h. The mixture was quenched with H2O (10 mL) and extracted with DCM (2 x 20 mL). The combined organics were washed with H2O (20 mL), brine (20 mL), dried (Na2SO4), and concentrated. The resulting material was purified by silica gel column chromatography (35% EtOAc/hexane) to provide the product as a colorless gum. [310 mg, 64%]

What are the applications of Application

Dichloromethane is an organic solvent used in the extraction of biological compounds