Chemical Properties
colourless gas
Chemical Properties
Ethylene oxide is the simplest cyclic ether. It is a colorless gas or liquid and has a sweet, etheric odor. Ethylene oxide is a flammable, very reactive and explosive chemical substance. On decomposition, vapors of pure ethylene oxide mix with air or inert gases and become highly explosive. Ethylene oxide, is used in large scale as an intermediate in the production of monoethylene glycol, diethylene glycol, triethylene glycol, poly(ethylene) glycols, ethylene glycol ethers, ethanolamine, ethoxylation products of fatty alcohols, fatty amines, alkyl phenols, cellulose, and poly(propylene glycol). It is also used as a fumigant for food and cosmetics, and in hospital sterilization of surgical equipment and heat sensitive materials.
Definition
ChEBI: A saturated organic heteromonocyclic parent that is a three-membered heterocycle of two carbon atoms and one oxygen atom.
Uses
Fumigant for foodstuffs and textiles; to sterilize surgical instruments; agricultural fungicide. In organic syntheses, especially in the production of ethylene glycol. Starting material for the manufacture of acrylonitrile and nonionic surfactants.
General Description
A clear colorless gas with an ethereal odor. Flash point below 0°F. May polymerize exothermically if heated or contaminated. If the polymerization takes place inside a container, the container may rupture violently. Vapors may burn inside a container. Vapors irritate the eyes, skin, and respiratory system. Prolonged skin contact may result in delayed burns. Less dense than water. Vapors heavier than air. Vapors very toxic. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. Used to make other chemicals, as a fumigant and industrial sterilant (AAR, 1999).
Reactivity Profile
Colorless gas at room temperature (b.p. 11°C), confirmed carcinogen. Highly flammable, severe explosion hazard when exposed to flame. The autoignition temperature may be as low as 140° C in presence of rust. Rapid compression of the vapor with air causes explosion. ETHYLENE OXIDE(75-21-8) vapor may be initiated into explosive decomposition in absence of air [Hess, L. G., et al., Ind. Eng. Chem., 1950, 42, p. 1251]. Metal fittings containing magnesium, copper or silver should be avoided, since traces of acetylene in ETHYLENE OXIDE(75-21-8) may produce metal acetylides capable of detonating the vapor [MCA SD-38, 1971]. Violent polymerization occurs on contact with strong bases (alkali hydroxides, ammonia) or acids, amines, metallic potassium, oxides (aluminum oxide, iron oxide, rust), covalent halides (aluminum chloride, ferric chloride, tin(IV) chloride) [Gupta, A. K., J. Soc. Chem. Ind., 1949, 68, p. 179]. Violent reaction with m-nitroaniline, magnesium perchlorate, mercaptans, thiols, triethylamine [Bretherick, 5th ed., 1995, p. 316]. ETHYLENE OXIDE(75-21-8) and SO2 can react violently in pyridine solution with pressurization if ETHYLENE OXIDE(75-21-8) is in excess (Nolan, 1983, Case History 51).
Air & Water Reactions
Highly flammable. Flammable over a wide vapor-air concentration range. Must be diluted on the order of 24 to 1 with water to lose flammability. Soluble in water.
Hazard
Irritant to eyes and skin. Confirmed carcinogen. Highly flammable, dangerous fire and
explosion risk, flammable limits in air 3–100%.
Health Hazard
ETHYLENE OXIDE can cause death. Lowest inhalation concentration causing toxic effects is 12500 ppm/10 seconds. It is a strong skin irritant. Neurological disorders and even death have been reported.
Health Hazard
Ethylene oxide is toxic by inhalation. Symptoms of overexposure include headache, dizziness, lethargy, behavioral disturbances, weakness, cyanosis, loss of sensation in the extremities, reduction in the sense of smell and/or taste, progressing with increasing exposure to convulsions, seizure and coma. Ethylene oxide is also an irritant to the skin and the respiratory tract, and inhaling the vapors may cause the lungs to fi ll with fl uid several hours after exposure. Inhalation may cause dizziness or drowsiness. Liquid contact may cause frostbite, and an allergic skin reaction. After oral exposure (ingestion) to ethylene oxide, laboratory animals show adverse effects in the blood, damage to the liver, kidneys, reproductive effects, miscarriages/spontaneous abortion, and cancer
Potential Exposure
Ethylene oxide is a man-made chemical used in the production of glycols (ethylene glycol, polyglycols, glycol ethers, esters), nontonic surface-active
agent; ethanolamines, acrylonitrile, plastics. It is also used
as a fumigant for foodstuffs and textiles; an agricultural
fungicide; and for sterilization, especially for surgical
instruments. It is used in drug synthesis and as a pesticide
intermediate
Fire Hazard
Severe explosion hazard when exposed to heat or flame. Irritating vapors are generated when heated. Vapor is heavier than air and may travel considerable distance to a source of ignition and flash back. Vapor forms explosive mixtures with air over a wide range. Liquid is not detonable but the vapor may be readily initiated into explosive decomposition. Avoid metal fittings containing copper, silver, mercury or magnesium; ammonia, oxidizing agents; acids, organic bases; amines; certain salts; alcohols; mercaptans, ferric chloride; magnesium perchlorate; m-nitroaniline; trimethylamine, potassium, tin chlorides; alkanethiols; bromoethane; aluminum chloride; aluminum oxide; iron chlorides; and iron oxides. Avoid air, heat, acids and bases, metal or metal chloride catalysts. Hazardous polymerization may occur. Avoid acids; covalent halides such as chlorides of aluminum, iron (III), tin (IV); basic materials like alkali hydrides, ammonia, amines, and potassium; catalytically active solids such as aluminum or iron oxides or rust, chlorides of boron, aluminum, tin, and iron; some carbonates; and metals such as copper and copper alloys
First aid
If ethylene oxide gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts
the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from
exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has
stopped and CPR if heart action has stopped. Transfer
promptly to a medical facility. When this chemical has
been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit. If frostbite has occurred, seek
medical attention immediately; do NOT rub the affected
areas or flush them with water. In order to prevent further
tissue damage, do NOT attempt to remove frozen clothing
from frostbitten areas. If frostbite has NOT occurred,
immediately and thoroughly wash contaminated skin with
soap and water. Medical observation is recommended for
24 to 48 hours after breathing overexposure, as pulmonary
edema may be delayed. As first aid for pulmonary edema,
a doctor or authorized paramedic may consider administering a drug or other inhalation therapy.
Shipping
UN1040 Ethylene oxide or Ethylene oxide with
nitrogen up to a total pressure of 1 MPa (10 bar) at 50℃,
Hazard Class: 2.3; Labels: 2.3-Poisonous gas, 2.1-
Flammable gas, Inhalation Hazard Zone D. Cylinders must
be transported in a secure upright position, in a wellventilated truck. Protect cylinder and labels from physical
damage. The owner of the compressed gas cylinder is the
only entity allowed by federal law (49CFR) to transport
and refill them. It is a violation of transportation regulations to refill compressed gas cylinders without the express
written permission of the owner
Incompatibilities
May form explosive mixture with air.
Chemically unstable. Dangerously reactive; may rearrange
chemically and/or polymerize violently with evolution of
heat; when in contact with highly active catalytic surfaces,
such as anhydrous chlorides of iron, tin and aluminum;
pure oxides of iron and aluminum; and alkali metal hydroxides. Even small amounts of strong acids; alkalis, or oxidizers can cause a reaction. Avoid contact with copper.
Protect container from physical damage, sun and heat.
Attacks some plastics, rubber or coatings.
Waste Disposal
Return refillable compressed
gas cylinders to supplier. Concentrated waste containing no
peroxides-discharge liquid at a controlled rate near a pilot
flame. Concentrated waste containing peroxides-perforation
of a container of the waste from a safe distance followed
by open burning
Occurrence
Reported found in Bantu beer.
Preparation
By catalytic oxidation of ethylene.
Production Methods
Ethylene oxide is currently produced by the direct oxidation
of ethylene with oxygen or air over a catalyst. Ethylene is
approximately 60% converted to the oxide at temperatures in
the range of 100–150℃. In the past, an indirect but more
general and more specific synthesis path consisted of adding
hypochlorous acid to olefins to form the chlorohydrins.
Subsequent treatment with strong bases results in dehydrochlorination
and the formation of the epoxide.
Aroma threshold values
Detection: 260 ppm; recognition: 500 ppm
Flammability and Explosibility
Ethylene oxide is an extremely flammable substance (NFPA rating = 4). Ethylene oxide vapor may be ignited by hot surfaces such as hot plates and static electricity discharges, and since the vapor is heavier than air, it may travel a considerable distance to an ignition source and flash back. Ethylene oxide vapor forms explosive mixtures with air at concentrations of 3 to 100% (by volume). Carbon dioxide or dry chemical extinguishers should be used for ethylene oxide fires. Ethylene oxide may explode when heated in a closed vessel.
Agricultural Uses
Fungicide and fumigant: Ethylene oxide is used as a fumigant for spices, seasonings,
and foodstuffs and as an agricultural fungicide.
When used directly in the gaseous form or in nonexplosive
gaseous mixtures with nitrogen or carbon dioxide, ethylene
oxide can act as a disinfectant, fumigant, sterilizing
agent, and insecticide. It is a man-made chemical used as
an intermediate in organic synthesis for ethylene glycol,
polyglycols, glycol ethers, esters, ethanolamines, acrylonitrile,
plastics, and surface-active agents. It is also used
as a fumigant for textiles and for sterilization, especially
for surgical instruments. It is used in drug synthesis and
as a pesticide intermediate. Not approved for use in EU
countries. Actively registered in the U.S.
Trade name
AMPROLENE®; ANPROLENE®;
ANPROLINE®; BIODAC®; MERPOL®; OXYFUME®;
OXYFUME 12®; T-GAS®; STERILIZING GAS
ETHYLENE OXIDE 100%®
Materials Uses
Steel and stainless steel are suitable materials
for equipment and piping in ethylene oxide
service. Dangerous runaway reactions can result
from contact with copper, silver, magnesium and their alloys; mercury and its salts; oxidizers
of all types; alkalis and acids; alcohols; mercaptans;
and alkali metals. Ethylene oxide will
polymerize violently if contaminated with aqueous
alkalis, amines, mineral acids, metal chlorides,
or metal oxides.
Physiological effects
Ethylene oxide is a toxic liquid and gas. Contact
of the eyes with liquid ethylene oxide can cause
severe irritation and corneal injury. Eye contact
with the vapor can cause moderate irritation.
Skin contact with the liquid or vapor or water
solutions can cause severe delayed chemical
bums. Inhalation of vapor will cause irritation
of the respiratory tract, which may result in
headache, nausea, and vomiting. All cases of
inhalation or contact with ethylene oxide liquid
or vapor must receive immediate first aid action
followed by medical attention.
Carcinogenicity
Ethylene oxide is known to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in humans, including epidemiological studies and studies on mechanisms of carcinogenesis. Ethylene oxide was first listed in the Fourth Annual Report on Carcinogens in 1985 as reasonably anticipated to be a human carcinogen based on limited evidence of carcinogenicity from studies in humansand sufficient evidence of carcinogenicity from studies in experimental animals. The listing was revised to known to be a human carcinogen in the Ninth Report on Carcinogens in 2000.
An increased risk of cancer has been demonstrated in epidemiological studies of workers using ethylene oxide as a sterilant for medical devices and spices and in chemical synthesis and production.Evidence for a common mechanism of carcinogenesis in humans and experimental animals comes from studies that have found similar genetic damage in cells of animals and workers exposed to ethylene oxide. The DNA-damaging activity of ethylene oxide explains its effectiveness as a sterilant, and this same property accounts for its carcinogenic risk to humans.
Environmental Fate
Ethylene oxide released to the environment partitions primarily
to the atmosphere due to its high volatility (vapor pressure
146 kPa at 20℃). Although the high water solubility of
ethylene oxide suggests it can be extracted from air by rainfall, its
rapid volatilization from water (half-life of 1 h) argues against
this process being a significant factor in its environmental fate.
In the atmosphere, ethylene oxide reacts with hydroxyl radicals
resulting in a half-life of 2–5 months. In freshwater, ethylene
oxide is hydrolyzed to ethylene glycol (half-life ～ 1 week); in
salt water, it is hydrolyzed to ethylene glycol and ethylene
chlorohydrin (half-life ～2 weeks). In unacclimated aqueous
media, ethylene oxide is also subject to biodegradation with
estimated half-lives of 1–6 months (aerobic) and 4–24 months
(anaerobic). However, in the presence of activated sludge,
ethylene oxide is readily biodegradable. Due to its high volatility
and water solubility, ethylene oxide is not expected to persist in
soil or sediments. The low log Kow (-0.30) for ethylene oxide
indicates little potential for bioaccumulation.
storage
work with ethylene oxide should be conducted in a fume hood to prevent exposure by inhalation, and appropriate impermeable gloves and splash goggles should be worn at all times to prevent skin and eye contact. Ethylene oxide should be used only in areas free of ignition sources and should be stored in the cold in tightly sealed containers placed within a secondary container.
Purification Methods
Dry oxirane with CaSO4, then distil it from crushed NaOH. It has also been purified by passage, as a gas, through towers containing solid NaOH. [Beilstein 17/1 V 3.]
Toxicity evaluation
The mechanisms of toxicity are not yet understood; however, it
is likely that, in general, the toxic effects of ethylene oxide are
due to its ability to react with cellular molecules, altering
function. Attempts to link the carcinogenicity of ethylene oxide
noted in experimental animals to ethylene oxide-induced DNA
adducts, including the major adduct formed (N7-hydroxyethyl
guanine), have been unsuccessful. Research on the mode of
action for ethylene oxide-induced carcinogenicity includes
work focused on the potential role of glutathione depletion
and the resulting oxidative stress, events that can occur after
exposure to high levels of ethylene oxide.
GRADES AVAILABLE
Ethylene oxide is sold only in grades of 99.7
percent or higher purity.
Ranges in specification values indicate a difference
in the limits given by different producers
[2].
