ChemicalBook > Product Catalog > Organic Chemistry > Hydrocarbons and derivatives > Hydrocarbon halides > Methylene Chloride
Methylene Chloride Chemical Properties
- Melting point:−97 °C(lit.)
- Boiling point:39.8-40 °C mm Hg(lit.)
- Density 1.325 g/mL at 25 °C(lit.)
- vapor density 2.9 (vs air)
- vapor pressure 24.45 psi ( 55 °C)
- refractive index n
- form Liquid
- color Colorless to yellow
- Relative polarity0.309
Methylene Chloride Usage And Synthesis
- DescriptionAlso known as methylenedichloride and dichloromethane,CH2Cl2 is a colorless, volatile liquid with a penetrating ether-like odor that is soluble in alcohol and ether,and slightly soluble in water. Non-flammable and nonexplosive in air. Derivation is the chlorination of methylchloride and subsequent distillation. It is used in paint removers,solvent degreasing, plastics processing. blowing agent in foams, solvent extraction, solvent for cellulose acetate,and as an aerosol propellant.
- Physical propertiesA common synonym for methylene chloride is dichloromethane.
Methylene chloride is a colorless liquid with a sweetish odor.
The chemical formula for methylene chloride is CH2Cl2, and the molecular weight is 84.93 g/mol.
The vapor pressure for methylene chloride is 349 mmHg at 20 °C, and it has an octanol/water coefficient (log K ow ) of 1.30.
Methylene chloride has an odor threshold of 250 parts per million (ppm).
Methylene chloride is slightly soluble in water and is nonflammable.
- UsesMethylene chloride is predominantly used as a solvent in paint strippers and removers; as a process solvent in the manufacture of drugs, pharmaceuticals, and film coatings; as a metal cleaning and finishing solvent in electronics manufacturing; and as an agent in urethane foam blowing.
Methylene chloride is also used as a propellant in aerosols for products such as paints, automotive products, and insect sprays.
It is used as an extraction solvent for spice oleoresins, hops, and for the removal of caffeine from coffee. However, due to concern over residual solvent, most decaffeinators no longer use methylene chloride.
Methylene chloride is also approved for use as a postharvest fumigant for grains and strawberries and as a degreening agent for citrus fruit.
- Health HazardMethylene chloride is predominantly used as a solvent. The acute (short-term) effects of methylene chloride inhalation in humans consist mainly of nervous system effects including decreased visual, auditory, and motor functions, but these effects are reversible once exposure ceases. The effects of chronic (long-term) exposure to methylene chloride suggest that the central nervous system (CNS) is a potential target in humans and animals. Human data are inconclusive regarding methylene chloride and cancer. Animal studies have shown increases in liver and lung cancer and benign mammary gland tumors following the inhalation of methylene chloride.
- Industrial usesMethylene chloride has been suggested, and indeed is already in commercial use, as a substitute for chlorofluorocarbon auxiliary blowing agents. Methylene chloride is highly volatile (boiling point 39.8°C) and inert in polyurethane-forming mixtures. However, methylene chloride is a suspected carcinogen and has other deleterious effects on workers exposed to it. Accordingly, the concentration of methylene chloride in the air inside a foam plant must be kept low. The American Conference of Governmental Industrial Hygienists recommends that workers not be exposed to more than 50 ppm of the chemical, while the Occupational Safety and Health Administration’s Permissible Exposure Limit is 500 ppm. Keeping the levels of methylene chloride in a foam plant below 50 ppm may require additional ventilation equipment, with an associated increase in costs. In addition, the chemical is a recognized environmental pollutant, and both the federal and state governments are beginning to limit releases of the chemical from plants that employ it. Thus, in the near future, plants using methylene chloride as an auxiliary blowing agent may be faced with the substantial additional expense of installing scrubbers or similar equipment to remove methylene chloride from air and/or other gases discharged from the plant. In addition, California has recently proposed that emissions of methylene chloride in that state be subject to a heavy “pollution” tax, and other states are likely to follow a similar course.
- Industrial usesMethylene chloride is used as a solvent, especially where high volatility is required.
It is a good solvent for oils, fats, waxes, resins, bitumen, rubber and cellulose
acetate and is a useful paint stripper and degreaser. It is used in paint removers, in
propellant mixtures for aerosol containers, as a solvent for plastics, as a degreasing
agent, as an extracting agent in the pharmaceutical industry, and as a blowing agent
in polyurethane foams. Its solvent property is sometimes increased by mixing with
methanol, petroleum naphtha, or tetrachloroethylene.
Methylene chloride is the active ingredient in many formulations of paint removers including industrial paint and commercial furniture strippers, home paint removers, and products used for aircraft maintenance. The chemical has a unique ability to penetrate, blister, and lift a wide variety of paint coatings. Formulations of the chemical are used extensively in both flow-over and immersion (dip) tanks in furniture refmishing operations. For the maintenance of military and commercial aircraft, a methylene chloride-based product is often required to inspect the surface for damage.
Since the mid-1990s methylene chloride has replaced 1,1,1-trichloroethane in nonflammable adhesive formulations for industrial applications, including fabrication of upholstery foam. It provides adhesive formulations with strong, instant bonding characteristics and efficacy under extremes of temperature and humidity. In foam applications, use of methylene chloride eliminates the possibility of hard seams and allows for ready compliance with flammability requirements for upholstered furniture.
Methylene chloride is used in aerosols as a strong solvent, a flammability suppressant, vapor pressure depressant, and viscosity thinner. Current aerosol uses of methylene chloride include spray paints and lubricants.
Methylene chloride is a leading auxiliary blowing agent used in the production of slabstock flexible polyurethane foams for the furniture and bedding industries. Methylene chloride is used as an extractant in the recovery and purification of a wide variety of materials including oils, fats, and waxes. The chemical is used for the decaffeination of coffee and tea, oleoresin extraction from a variety of spices, and for the extraction of hops. As with tablet coatings, little or none of the chemical remains in the finished product.
- Potential ExposureThe principal route of human exposure to methylene chloride is inhalation of ambient air.
Occupational and consumer exposure to methylene chloride in indoor air may be much higher, especially from spray painting or other aerosol uses. People who work in these places can breathe in the chemical or it may come in contact with the skin.
Methylene chloride has been detected in both surface water and groundwater samples taken at hazardous waste sites and in drinking water at very low concentrations.
- storagePrior to working with Methylene Chloride you should be trained on its proper handling and storage.
A regulated, marked area should be established where Methylene Chloride is handled, used or stored as required by the OSHA Methylene Chloride Standard (29 CFR 1910.1052).
Methylene Chloride reacts violently With OXIDIZING AGENTS(such as PERCHLORATES, PEROXIDES PERMANGANATES CHLORATES NITRATES CHLORINE, BROMINE and FLUORINE CHEMICALLY ACTIVE METALS (such as POTASSIUM, SODIUM MAGNESIUM and ALUMINUM) and STRONG BASES(such as SODIUM HYDROXIDE and POTASSIUM HYDROXIDE).
Methylene Chloride is not compatible with liquid oxygen;Titanium and Amines.
Store in tightly closed containers in a cool, well-ventilated area away from Metals and Ligh.
Methylene Chloride attacks some forms OFPLASTIC RUBBER and COATINGS and will corrode iron. some STAINLESS STEELS COPPER and NICKEL in the presence of WATER.
Methylene Chloride Preparation Products And Raw materials
- Company Name:Spectrum Chemical Manufacturing Corp.
- Company Name:HBCChem, Inc.