Acetilén

Acetilén (C2H2) is the simplest of the alkynes and a colorless, flammable gas. It contains a triple bond between two carbon atoms and is linear. At room temperature it is a gas; its boiling point is −84 °C. Acetilén is typically stored under pressure in stabilized form because the pure gas can decompose violently when compressed.

In commercial products, acetilén is dissolved in a solvent such as acetone with a porous filler to prevent polymerization. Industrially, it is produced primarily by reacting calcium carbide with water: CaC2 + H2O → C2H2 + Ca(OH)2. It is generated on demand for welding and metal cutting, where it forms a high-temperature flame when burned with oxygen in an oxyacetylene torch.

Acetilén is a versatile building block in organic synthesis: it is a key feedstock for vinyl chloride monomer used to make PVC and serves as a precursor to various other chemicals. It is also used in several reactions that form aldehydes, acetaldehyde derivatives, and other acetylene-based compounds.

Safety and handling: Acetilén is highly flammable and can act as an asphyxiant in suffocating concentrations. Leaks can accumulate in enclosed spaces, so ignition sources must be avoided. In cylinders, acetilén must be kept away from heat and secure from shock. Pure acetilén and some metal surfaces can form explosive acetylides, so high-pressure storage and certain metal contacts are avoided.

See also: vinyl chloride, calcium carbide, oxyacetylene welding.