Chloromethanes

The term chloromethanes characterizes the family of four chlorinated methane derivatives. They are distinguished according to their degree of chlorination:

• methyl chloride or monochloromethane CH ₃ Cl ;

• methylene chloride or dichloromethane CH ₂ Cl ₂ ;

• chloroform or trichloromethane CHCl ₃ ;

• carbon tetrachloride or tetrachloromethane CCl ₄ .

The first is gaseous under normal temperature and pressure conditions, while the other three are liquid.

Their synthesis involves either chlorination of methane, or hydrochlorination of methanol to methyl chloride, which may be followed by chlorination.

The industrial importance of this product family lies mainly in the following three areas:

• use as solvents ;

• use as intermediates in the manufacture of chlorofluorocarbons and fluorocarbons for higher chloromethanes ;

• methyl chloride for use in silicone manufacture.