Dichloromethane (cas:75-09-2)

Dichloromethane is a compound formed when two hydrogen atoms in a methane molecule are replaced by chlorine, with the molecular formula CH2Cl2. It is a colorless, transparent liquid that is heavier than water and easily volatile, with an ether-like odor and a sweet taste. It is non-flammable but can form explosive mixtures when mixed with high concentrations of oxygen. Dichloromethane is slightly soluble in water and miscible with most commonly used organic solvents. It can also be mixed in any proportion with other chlorinated solvents, ether, ethanol, and N,N-dimethylformamide. At room temperature, dichloromethane is poorly soluble in liquid ammonia but dissolves quickly in phenols, aldehydes, ketones, glacial acetic acid, triethyl phosphate, formamide, cyclohexylamine, and ethyl acetoacetate. Its relative density is 1.3266 (20/4°C). Melting point -95.1°C, boiling point 40°C. It is a non-flammable, low-boiling solvent commonly used to replace flammable solvents such as petroleum ether and ether, and can also serve as a local anesthetic in dentistry, a refrigerant, and a fire-extinguishing agent. Autoignition temperature is 640°C. Viscosity (20°C) is 0.43 mPa·s. Refractive index nD(20°C) 1.4244. Critical temperature 237°C, critical pressure 6.0795 MPa. Thermal decomposition produces HCl and trace amounts of phosgene. When heated with water for a long time, it generates formaldehyde and HCl. Further chlorination can yield CHCl3 and CCl4.