What Is Another Name for Dichloromethane?
Dichloromethane, CAS 75-09-2, is also called methylene chloride, methylene dichloride, or simply DCM. All of these names refer to the same organic solvent, with the molecular formula CH2Cl2. It is a clear, colourless liquid with a mild, sweet odour, and it is highly volatile, so it evaporates quickly at room temperature.
Because both the systematic name and the shorter trade name are in daily use, buyers should match the CAS number 75-09-2 on the label, the safety data sheet and the certificate of analysis rather than rely on the name printed on the drum.
Key Physical and Chemical Properties
| Property | Value |
|---|---|
| CAS number | 75-09-2 |
| Alternative names | Methylene chloride; methylene dichloride; DCM |
| Molecular formula | CH2Cl2 |
| Appearance | Clear, colourless liquid with a mild, sweet odour |
| Melting point | -96.7 °C |
| Boiling point | 39.8 °C |
| Vapour density (air = 1) | 2.93 |
| Specific gravity | 1.3255 |
| Solubility in water | Slightly soluble |
| Stability | Chemically stable under normal conditions |
The boiling point of 39.8 °C means the liquid boils below body temperature, so it evaporates very readily at ambient conditions. Its vapour density of 2.93 relative to air means the vapour is heavier than air and tends to collect in low-lying areas such as pits and trenches, where it can displace air in confined spaces.
Main Industrial Applications
Dichloromethane is primarily used as a powerful solvent in paint strippers, where it softens and lifts old coatings from metal, wood and masonry surfaces.
Paint strippers and coating removal formulations for industrial refurbishment.
Metal cleaning and degreasing before welding, coating or assembly.
Processing agent in the manufacture of pharmaceuticals.
Selective extraction of desired components from natural materials, including food extracts.
Adhesive formulations, foam blowing and laboratory extraction procedures.
In each of these duties the solvent is chosen for the same combination of properties: high solvency for resins, waxes and oils, rapid evaporation that leaves no residue, and non-flammability under normal handling conditions.
Regulatory Context and Health Considerations
Because of the health risks associated with exposure, the use of dichloromethane is heavily regulated in many countries. It is classified as a suspected carcinogen, and prolonged inhalation of high vapour concentrations can cause dizziness, headache and reduced awareness. Regulations in regions such as the European Union restrict its use in consumer paint strippers, and industrial users must implement strict ventilation, closed systems and exposure monitoring.
Work under local exhaust ventilation or in a closed system, and monitor airborne concentrations.
Wear suitable chemically resistant gloves, eye protection and, where required, respiratory protection.
Never use the solvent in a confined space without forced ventilation and atmospheric testing.
Always handle the material in accordance with the safety data sheet and local occupational exposure limits.
Packaging, Purity and Supply Considerations
Dichloromethane is supplied in a range of packages to suit different logistics needs. Common options include 1050 kg intermediate bulk containers with approximately 21 tons per 20-foot container, and 200 kg drums with approximately 16 tons per 20-foot container.
Verify the purity specification and the water content required for the intended process.
Request the certificate of analysis and the safety data sheet with every batch.
Confirm that the packaging meets the transportation regulations for hazardous liquids.
Check that the container lining and closures are compatible with chlorinated solvents.
Frequently Asked Questions
Q: What is another name for dichloromethane?
Dichloromethane is also called methylene chloride, methylene dichloride, or DCM.
Q: What is the CAS number of dichloromethane?
The CAS number of dichloromethane is 75-09-2, and its molecular formula is CH2Cl2.
Q: What is the boiling point of dichloromethane?
The boiling point is 39.8 °C and the melting point is -96.7 °C, so the solvent is highly volatile at room temperature.
Q: What is dichloromethane used for?
It is used as a solvent in paint strippers and metal cleaning, and as a processing agent in pharmaceutical and food extract production.
Q: Is dichloromethane soluble in water?
It is only slightly soluble in water, but it dissolves a wide range of organic materials, which is why it is used for extraction.
Q: Why is dichloromethane use regulated?
It is regulated because of health risks that include classification as a suspected carcinogen and effects on the nervous system after high exposure.
Q: How should dichloromethane vapour be controlled?
Because the vapour is heavier than air, use local exhaust ventilation or closed systems, test low-lying areas before entry and monitor worker exposure.