Under increased temperature and pressure, pyridines including DMAP can react with DCM to form methylene bispyridinium dichlorides. Secondary amines can react with DCM to yield an equilibrium of iminium chlorides and chloromethyl chlorides, which can react with a second equivalent of the secondary amine to form aminals. Tertiary amines can react with DCM to form quaternary chloromethyl chloride salts via the Menshutkin reaction. Methyllithium reacts with methylene chloride to give chlorocarbene (CHCl).ĭichloromethane reacts with certain amines under ambient temperature and pressure. Tert-butyllithium deprotonates DCM: H 2CCl 2 + RLi → HCCl 2Li + RH It does participate in reactions with certain strong nucleophiles however. It is used as the principal component of various paint and lacquer strippers.ĭichloromethane is widely used as a solvent in part because it is relatively inert. ĭichloromethane extract of Asparagopsis taxiformis, a seaweed fodder for cattle, has been found to reduce their methane emissions by 79%. It is used in the garment printing industry for removal of heat-sealed garment transfers.ĭCM is used in the material testing field of civil engineering specifically it is used during the testing of bituminous materials as a solvent to separate the binder from the aggregate of an asphalt or macadam to allow the testing of the materials. Often sold as a main component of plastic welding adhesives, it is also used extensively by model building hobbyists for joining plastic components together. For example, it is used to seal the casing of electric meters. It is also used as the fluid in jukebox displays and holiday bubble lights that have a colored bubbling tube above a lamp as a source of heat and a small amount of rock salt to provide thermal mass and a nucleation site for the phase changing solvent.ĭCM chemically welds certain plastics. An example of a DCM heat engine is the drinking bird. The chemical compound's low boiling point allows the chemical to function in a heat engine that can extract mechanical energy from small temperature differences. Specialized uses Near IR absorption spectrum of dichloromethane showing complicated overlapping overtones of mid IR absorption features. The donor hydrogen-bonding corrections of methylene chloride in these thermodynamic studies has been reported. It is a solvent that has been used in many thermodynamic studies of donor-acceptor bonding. It is classified as a hard acid and is included in the ECW model. Methylene chloride is a Lewis acid that can hydrogen bond to electron donors. Its volatility has led to its use as an aerosol spray propellant and as a blowing agent for polyurethane foams. In the food industry, it is used to decaffeinate coffee and tea as well as to prepare extracts of hops and other flavourings. Uses ĭCM's volatility and ability to dissolve a wide range of organic compounds makes it a useful solvent for many chemical processes. These compounds are separated by distillation.ĭCM was first prepared in 1839 by the French chemist Henri Victor Regnault (1810–1878), who isolated it from a mixture of chloromethane and chlorine that had been exposed to sunlight. The output of these processes is a mixture of chloromethane, dichloromethane, chloroform, and carbon tetrachloride as well as hydrogen chloride as a byproduct. CH 4 + Cl 2 → CH 3Cl + HCl CH 3Cl + Cl 2 → CH 2Cl 2 + HCl CH 2Cl 2 + Cl 2 → CHCl 3 + HCl CHCl 3 + Cl 2 → CCl 4 + HCl In this way, an estimated 400,000 tons were produced in the US, Europe, and Japan in 1993. At these temperatures, both methane and chloromethane undergo a series of reactions producing progressively more chlorinated products. Production ĭCM is produced by treating either chloromethane or methane with chlorine gas at 400–500 ☌. However, the majority of dichloromethane in the environment is the result of industrial emissions. Natural sources of dichloromethane include oceanic sources, macroalgae, wetlands, and volcanoes. Although it is not miscible with water, it is slightly polar, and miscible with many organic solvents. This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Dichloromethane ( DCM, methylene chloride, or methylene bichloride) is an organochlorine compound with the formula C H 2 Cl 2.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |