Acetylen

Acetylen, also known as ethyne, is a hydrocarbon with the formula C2H2. It is the simplest member of the alkynes and features a carbon–carbon triple bond. The molecule is linear, with a bond angle of about 180 degrees. At room temperature, acetylene is a colorless, highly flammable gas that is only sparingly soluble in water but dissolves readily in many organic solvents.

Industrial production of acetylene mainly occurs via the calcium carbide process. Calcium carbide reacts with water to form acetylene and calcium hydroxide: CaC2 + H2O → C2H2 + Ca(OH)2. Calcium carbide is produced by heating calcium oxide with coke at high temperatures. Acetylene can also be generated on a smaller scale by other reforming or decomposition routes, but the calcium carbide method is the principal industrial source. In commercial practice, acetylene is stored and transported as a stabilized solution in solvents such as acetone or dimethylformamide within pressure-rated cylinders to suppress polymerization of the gas.

Applications of acetylene are diverse. It is widely used as a fuel for welding and metal cutting when burned with oxygen, producing a flame with temperatures around 3,100 °C. As a versatile chemical feedstock, acetylene serves as a starting material for the synthesis of numerous organic compounds, including vinyl chloride monomer for polyvinyl chloride (PVC) and various acetyl-containing chemicals.

Safety and handling are important due to its high flammability and tendency to form explosive mixtures with air. Acetylene can polymerize under certain conditions, especially at high pressure when stored in pure form; commercially it is stabilized (commonly as a solvated gas with acetone) to mitigate this risk. Proper storage, ventilation, and separation from oxidizers are required.