The high reactivity of halogens has made them one of the most useful elements in the periodic table. Polyhalogen is one of the classes of compounds formed by the halogen group elements. These compounds are characterised by the presence of two or more halogen groups as the substituents in the compounds. Apart from being highly reactive, compounds of halogens are sometimes highly toxic and carcinogenic. This has led to an intensive study on these compounds and their effect on the environment. Dichloromethane, also known as methylene dichloride or methylene chloride (more commonly) is one of the many polyhalogen compounds that have found application in many industries. Chemically, formula for methylene dichloride is CH2Cl2.
Dichloromethane is used as solvent in many industries. It is also finds application as a paint remover.
Some of the drug manufacturing companies use methylene chloride as a process solvent. It is also used in aerosols as a propellant. Methylene chloride is also used in the processing of coffee and tea to decaffeinate them. It is also used for hop extraction and providing flavours. Owing to its high volatility, polymer industries use dichloromethane as a blowing agent especially for polyurethane products. It has also been used in adhesives industry and for sealing plastic cases.
There may be an endless list of uses and application of methylene chloride, but its utility cannot cast a shadow on its toxicity. Although it is one of the least toxic poylhalogenated compounds, its harmful effect on human body is not unknown. It affects the central nervous system of the human body. Even a slight exposure to dichloromethane can cause hearing and vision impairments. In case of direct contact with human skin, it causes redness of the skin along with intense burning. Exposure to methylene chloride in high doses leads to numbness in fingers, dizziness, tingling, and nausea. Continuous exposure to methylene chloride causes irritation in respiratory tracks, difficulty in concentrating, headache and eye irritation. Studies have shown its carcinogenic properties, it causes lungs, liver and pancreatic cancer in animals.
Many countries use warnings on products that have dichloromethane in them. Some countries have banned the use of methylene chloride. Indian industries continue to use methylene dichloride with certain regulations from the government. Scientists are working hard to develop the alternatives of dichloromethane. Log on to Byju’s YouTube channel to explore more about the poylhalogenated compounds.