Ethylene oxide (EO) is a widely used organicintermediate, also known as oxirane, epoxy ethane,1,2-epoxyaethane, 1,2-epoxyethane, aethylenoxid,oxane.

At ambient temperature and pressure, ethylene oxide iscolorless gas, miscible with water and most organic solvents, with etherfragrance and mild narcotic; Ethylene oxide with density of 0.87g/cm3, melting point of -111.3 ℃, the boiling point of 10.7 ℃, viscosity of 0.03 Pas, flashpoint ＜-18 ℃ the spontaneous point of 429 ℃, explosion limit of 3-100%; Ethylene oxide is flammable,high temperature and open fire can cause the risk of combustion explosion, themaximum allowable concentration in the air 0.001 g/m3; Ethyleneoxide has certain toxicity, the allowable concentration in the air of 50ppm.

Ethylene oxide has three-member ring structure, has very activechemical properties, and can take part in open ring addition reaction,isomerization, oxidation, reduction, carbonylation and self polymerization withmany compounds.

At present, the world's annual production of ethyleneoxide is more than 20 million tons and the position of ED is after polyethylenein the ethylene industry. EO mainly used in the manufacture of ethylene glycol,synthetic detergent, emulsifying agent, softening agent, lubricant,bactericide, water reducing agent, antifreeze agent, plasticizer, insecticide,warehouse fumigant, synthetic fibers, explosives and rocket jet fuel.

The initial method for the production of ethylene oxideis chlorohydrination process. Due to high energy consumption and pollution, thechlorohydrinationhas been eliminated in the world.

In 1931 the world's first patent of the direct oxidationof ethylene in the silver catalyst for ethylene oxide production was published,and in 1938 the first set of air production of ethylene oxide productionequipment was built, the production of ethylene oxide transformed into ethylenedirect oxidation from the chlorohydrination process with severe pollution. Directoxidation method is divided into two kinds: air method and oxygen method. Theformer uses air as oxidant, because its selectivity is low, and it was replacedby the latter which costs lower. The latter uses oxygen (more than 95% volumefraction) as oxidant. After continuous improvement of catalyst and productionprocess, the direct oxidation of ethylene becomes the main source of ethyleneoxide.

The industrial production process of direct oxidation methodis divided into three parts: epoxidation, ethylene oxide recovery and ethyleneoxide refining.