Ethylene Oxide is an organic compound with the formula C2H4O. It is a colorless, toxic, highly flammable and explosive gas having a faintly sweet odor. It is colorless at 25 °C and is a mobile liquid at 0 °C – viscosity of liquid ethylene oxide at 0 °C is about 5.5 times lower than that of water. Ethylene Oxide is readily soluble in water, ethanol, diethyl ether and many organic solvents. It is the simplest epoxide: a three-membered ring consisting of one oxygen atom and two carbon atoms. Because of its special molecular structure, ethylene oxide easily participates in addition reactions; e.g., opening its ring and thus easily polymerizing. It can penetrate readily and can pass into the lumen of small tubes and through fabrics, paper and many, but not all, plastics. It is isomeric with acetaldehyde and with vinyl alcohol.
Commercial production of Ethylene Oxide dates back to 1914 when Chlorohydrins Process (reaction of Ethylene Chlorohydrins with Calcium Hydroxide) was used. More efficient direct oxidation of Ethylene by air was invented in 1931. It was further improved in 1958 by replacing air with Oxygen and using elevated temperature of 200–300 °C and pressure (1–3 MPa).
Subsequently, direct oxidation of ethylene method was repeatedly modified for industrial use and at least four major variations are known. They all use oxidation by oxygen or air and a silver-based catalyst but differ in the technological details and hardware implementations.
Ethylene Oxide is very useful chemical and has got huge consumptions in different industries. Prominently Ethylene Oxide is used: