Main Uses Of Ethylene Oxide (EO)
Ethylene oxide (EO) is the simplest cyclic ether, belonging to heterocyclic compounds, and is an important petrochemical product. Ethylene oxide is a colorless transparent liquid at low temperatures and a colorless gas with an irritating odor of ether at room temperature. The vapor pressure of the gas is high, reaching 141kPa at 30°C. This high vapor pressure determines that ethylene oxide has strong penetration during fumigation disinfection.
Ethylene oxide is the second generation of chemical disinfectants after formaldehyde. It is still one of the best cold disinfectants and the most important member of the four major low-temperature sterilization technologies (low-temperature plasma, low-temperature formaldehyde steam, ethylene oxide, glutaraldehyde). EO is a simple epoxy compound, a non-specific alkyl compound with a molecular formula of C2H4O and a molecular weight of 44.05.
Ethylene oxide is a toxic carcinogen that was previously used to make bactericides. Ethylene oxide is flammable and explosive, and is not easy to transport over long distances, so it has a strong regionality. It is widely used in washing, pharmaceuticals, printing and dyeing and other industries. It can be used as a starter for cleaning agents in chemical-related industries.
Ethylene oxide has a bactericidal effect, is non-corrosive to metals, has no residual odor, can kill bacteria (and their endospores), molds and fungi, and can therefore be used as a gas sterilant to sterilize some items and materials that cannot withstand high-temperature sterilization. In 1938, American chemist Lloyd Hall obtained a patent for the preservation of spices using ethylene oxide sterilization, and this method is still used by some people. Ethylene oxide is also widely used to sterilize medical supplies such as bandages, sutures and surgical instruments.
It is mainly used to manufacture various other solvents (such as cellosolves, etc.), diluents, non-ionic surfactants, synthetic detergents, antifreeze agents, disinfectants, toughening agents and plasticizers. Hydroxyethylation with cellulose can synthesize water-soluble resins (whose ethylene oxide content is about 75%). It can also be used as a fumigant, paint thickener, emulsifier, adhesive and paper sizing agent, etc.
Usually, a mixture of ethylene oxide-carbon dioxide (the ratio of the two is 90:10) or ethylene oxide-dichlorodifluoromethane is used, which is mainly used for disinfection of hospitals and precision instruments. Ethylene oxide fumigants are often used for the preservation of grain and food. For example, dry egg powder is often decomposed by bacteria during storage. Fumigation with ethylene oxide can prevent deterioration, and the chemical composition of the egg powder, including amino acids, is not affected.
Ethylene oxide easily reacts with acid, so it can be added to certain substances as an antacid to reduce the acidity of these substances or use it for a long time without producing acidity. For example, in the production of chlorinated butyl rubber, if ethylene oxide is added to the solution of isobutylene and isoprene copolymer before chlorination, the finished product can be completely free of alkali washing and water washing.
Because ethylene oxide is flammable and has a wide range of explosive concentrations in the air, it is sometimes used as a fuel component of fuel gasification bombs.
Ethylene oxide can generate huge energy when it decomposes automatically. It can be used as a power source for rockets and jet propulsion. It is generally a mixture of nitromethane and ethylene oxide (60:40 - 95:5). This mixed fuel has good combustion performance, low freezing point, relatively stable properties, and is not easy to detonate. In general, the consumption of ethylene oxide for the above direct uses is very small. Ethylene oxide is the second most important product as an industrial derivative of ethylene, second only to polyethylene. Its importance lies mainly in the series of products produced with it as a raw material. The types of downstream products derived from ethylene oxide are far more than various ethylene derivatives. The toxicity of ethylene oxide is 27 times that of ethylene glycol, which is similar to the toxicity of ammonia. Formation of formaldehyde, ethylene glycol and oxalic acid in the body has an anesthetic effect on the central nervous system, an irritant effect on mucous membranes, and a toxic effect on cell protoplasm.
Most of the ethylene oxide is used to make other chemicals, mainly ethylene glycol. The main end use of ethylene glycol is the production of polyester polymers, and it is also used as an automotive coolant and antifreeze. Secondly, it is used to produce downstream products such as ethoxylates, ethanolamines, glycol ethers, ethyleneamines, diethylene glycol, triethylene glycol, polyglycol, hydroxyethyl cellulose, choline chloride, glyoxal, ethylene carbonate, etc.
Ethylene oxide is mainly used to manufacture ethylene glycol (raw material for polyester fiber), synthetic detergents, non-ionic surfactants, antifreeze agents, emulsifiers, and glycol condensate products. It is also used to produce plasticizers, lubricants, rubber and plastics. It is widely used in many fields such as laundry, electronics, medicine, pesticides, textiles, papermaking, automobiles, oil extraction and refining, etc.
