Acetylene, << uh SEHT uh leen, >> also called ethyne, is a colorless, flammable gas used for welding and for preparing other chemical compounds. Its chemical formula is C2H2. Acetylene is poisonous if inhaled. It also forms explosive mixtures with air. Edmund Davy, an English chemist, first produced acetylene in 1836. The gas was forgotten until 1860, when the French chemist Marcellin Berthelot discovered a way to synthesize the gas from carbon and hydrogen, using an electric arc.
Acetylene mixed with oxygen produces a flame that reaches a temperature of about 6000 °F (3316 °C). This flame, called the oxyacetylene flame, is used to weld and cut metals. In welding, the edges of the metal are melted by the flame and then fused together. In cutting, the metal to be cut is heated but not melted by the oxyacetylene flame. Then a fine stream of oxygen is sprayed onto the metal. The oxygen burns through the metal, leaving a clean-cut edge. See Welding .
Acetylene also serves as a raw material in the preparation of certain chemical compounds used to manufacture plastics. These compounds include vinyl chloride, vinyl acetate, and 1,4-butanediol. In addition, acetylene is used in the manufacture of vitamins.
Acetylene may be produced commercially by creating a chemical reaction between calcium carbide and water. It is also made in industry by decomposing methane at high temperatures. Acetylene is stored in cylinders under high pressure. If not properly handled, the compressed gas can break down chemically and explode. To prevent explosions, acetylene is dissolved in acetone in special cylinders. In this manner, it can be safely shipped and stored.
See also Acetone ; Calcium carbide ; Hydrocarbon .
