Chloromethane

Chloromethane, commonly called methyl chloride, is the simplest chlorinated hydrocarbon, with the formula CH3Cl. It is a colorless gas at room temperature, has a boiling point of -24.2 °C, and is moderately soluble in water. It is a volatile organic compound used as a chemical building block and, historically, as a solvent and refrigerant.

Production and purification: Chloromethane is primarily produced by chlorinating methane, CH4 + Cl2 → CH3Cl + HCl, with further chlorination yielding higher chlorinated methanes. It can also be prepared from methanol and hydrogen chloride: CH3OH + HCl → CH3Cl + H2O. Purification removes water, unreacted methane, and higher chlorinated methanes.

Applications: Methyl chloride serves as a reagent in chloromethylation reactions and as a solvent in various industrial processes. It is also a feedstock for the production of more complex chlorinated compounds. Its use as a refrigerant has declined due to safety and environmental considerations, and today it is primarily valued as an industrial chemical precursor.

Safety and environmental: Chloromethane is toxic if inhaled, with effects including dizziness, headaches, and central nervous system depression; prolonged exposure can impact liver and kidney function. It is flammable and heavier than air, so leaks can accumulate in low-lying spaces. Handling requires appropriate containment and adherence to occupational safety limits. In the environment, it is subject to atmospheric degradation and contributes to chlorinated compound inventories.