Dichlorométhane

The dichlorométhane or chloride methylene is a chemical Composé used mainly like Solvant for the made up organics. It is a colorless and volatile liquid emitting relatively strong odor douceâtre but which badly returns certain people at ease.

The methylene chloride was obtained for the first time in 1840 by the French chemist Henri Victor Regnault, which isolated it from a mixture of Chlorométhane and Chlore previously exposed to the light.

Production

In industry, the dichlorométhane is produced by reaction of the Chlorométhane or the Méthane with the Chlore gas between 400 and 500°C. At these temperatures, as well methane as chloromethane undergo a series of reactions which gradually form increasingly chlorinated products.

CH4 + Cl2 → CH3Cl + HCl

CH3Cl + Cl2 → CH2Cl2 + HCl
CH2Cl2 + Cl2 → CHCl3 + HCl
CHCl3 + Cl2 → CCl4 + HCl

The result of this series of reaction is a mixture of Chlorométhane, dichlorométhane, Chloroforme and Carbon tetrachloride. These compounds are then separated by Distillation.

Uses

Its volatile character and its capacity to dissolve a large panoply of organic compounds make dichlorométhane an ideal solvent for many chemical processes. One makes use of it mainly like pickling solution for painting or grease-remover. In food industry, one makes use of it to decaffeinate the coffee and to prepare extracts of various flavors such as hop. As it is volatile, one also makes use of it like engine for spray and agent foaming to obtain the polyurethane foam. One also makes use of it like pesticide to store the strawberries and cereals. As it is not completely inoffensive for health, one however sought alternatives to the majority of his applications.

Dangers

The dichlorométhane is the least toxic of the simple chlorohydrocarbones but it is anyway not without risks. A chronic exposure to the dichlorométhane can be Carcinogène. Indeed, one could correlate it with a greater incidence of Cancer of the Poumons, Foie and Pancréas in animals of laboratory. It is a Mutagène and a Tératogène, causing malformations of the fetus so expectant mothers are exposed there during the Grossesse. The contact prolonged with the skin to little cause irritation or burns by dissolution of greasy fabrics.

In much of country, the products containing of the dichlorométhane must carry labels informing of its dangers to health. However, one often confuses it with the gasoline of Térébenthine or the White spirit, which presents less risks in particular for the skin.

Sentences of risk and councils of prudence according to the INRS

Rules Labelling

R40 - Possibility of irreversible effects.

S23 - not to breathe the vapors.

S24/25 - To avoid the contact with the skin and the eyes.

S36/37 - To wear clothing protective and gloves suitable.

External bonds

  • toxicological Card of the INRS
  • International Card of Safety

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