Physical property

A pungent odor similar to ether.

Steam pressure: 30.55 kPa (10 C)

Melting point: - 95.1 C

Relative density: 1.3266 (20/4 C) Spontaneous ignition point: 640 C.

Viscosity (20 C): 0.43 mPa.s.

Refractive index nD (20 C): 1.4244.

The critical temperature is 237 C.

Critical pressure: 6.0795 MPa.

Polarity: 3.4.

Absorption wavelength: 245.

Solubility: insoluble in water, soluble in phenol, aldehyde, ketone, glacial acetic acid, triethyl phosphate, ethyl acetoacetate, cyclohexylamine. It is miscible with other chlorinated hydrocarbon solvents such as ethanol, ether and N, N-dimethylformamide.

After pyrolysis, HCl and trace phosgene are produced, which are heated with water for a long time to produce formaldehyde and HCl. CHCl3 and CCl4 can be obtained by further chlorination. Colorless volatile liquid, difficult to burn. Dichloromethane reacts with sodium hydroxide to produce formaldehyde by partial hydrolysis at high temperature. In industry, dichloromethane is produced by the reaction of natural gas and chlorine gas, and purified by distillation. It is an excellent organic solvent. It is often used to replace flammable petroleum ether and ether, and can be used as local dental anesthetics, refrigerants and fire extinguishers. The irritation to skin and mucosa is slightly stronger than chloroform. Attention should be paid to the use of high concentration of dichloromethane.