Dichloromethane (CH2Cl2) – Dichloromethane is a clear, colorless organic solvent that has a sweet but mild odor and does not occur naturally in the environment. Its principle use is as a solvent in paint removers and as an aerosol propellant in paints and automotive spray products. In addition, it is used as a blowing and cleaning agent of metal, as a solvent in the production of polycarbonate resins, and in film processing, as well as many other industrial applications. In the food industry, it is used as an extraction solvent for caffeine, spices, and hops. All of these applications result in the release of dichloromethane into the environment, with the primary sources being the industries that manufacture the chemical or use it in production, such as the plastic and synthetics manufacturers, as well as the electronics industry. Upon release of the liquid chemical into the environment, dichloromethane quickly evaporates to a gas, where it is then degraded by photochemically produced products in the air. Because of its reactivity in the troposphere, it is not believed to react with ozone in the upper atmosphere. Despite its solubility in water, it has low acute toxicity to aquatic animals. In animals (as well as humans), dichloromethane is metabolized into carbon monoxide, which has a higher affinity for the heme groups in hemoglobin than does oxygen and results in deprivation of oxygen. Interestingly, dichloromethane has been found to be an antisickling agent in sickle cell hemoglobin.
[Proceedings of the National Academy of Sciences of the United States of America, v 73(11); 1976; 4195-4199.]
[Science, v 176(4032); 1972; 295-296]
Atmospheric Chemistry Glossary |
