Ethylene oxide is an organic compound with the formula C2H4O. It is a cyclic ether and the simplest epoxide: a three-membered ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless and flammable gas with a faintly sweet odor. Because it is a strained ring, ethylene oxide easily participates in a number of addition reactions that result in ring-opening. Ethylene oxide is isomeric with acetaldehyde and with vinyl alcohol. Ethylene oxide is industrially produced by oxidation of ethylene in the presence of a silver catalyst. The reactivity that is responsible for many of ethylene oxide's hazards also makes it useful. Although too dangerous for direct household use and generally unfamiliar to consumers, ethylene oxide is used for making many consumer products as well as non-consumer chemicals and intermediates. These products include detergents, thickeners, solvents, plastics, and various organic chemicals such as ethylene glycol, ethanolamines, simple and complex glycols, polyglycol ethers, and other compounds. Although it is a vital raw material with diverse applications, including the manufacture of products like polysorbate 20 and polyethylene glycol (PEG) that are often more effective and less toxic than alternative materials, ethylene oxide itself is a very hazardous substance. At room temperature it is a very flammable, carcinogenic, mutagenic, irritating; and anaesthetic gas. Ethylene oxide is a surface disinfectant that is widely used in hospitals and the medical equipment industry to replace steam in the sterilization of heat-sensitive tools and equipment, such as disposable plastic syringes. It is so flammable and extremely explosive that it is used as a main component of thermobaric weapons; therefore, it is commonly handled and shipped as a refrigerated liquid to control its hazardous nature.
History Ethylene oxide was first reported in 1859 by the French chemist Charles-Adolphe Wurtz, who prepared it by treating 2-chloroethanol with potassium hydroxide:
Cl−CH2CH2−OH + KOH → (CH2CH2)O + KCl + H2O Wurtz measured the boiling point of ethylene oxide as 13.5 °C (56.3 °F), slightly higher than the present value, and discovered the ability of ethylene oxide to react with acids and salts of metals. Wurtz mistakenly assumed that ethylene oxide has the properties of an organic base. This misconception persisted until 1896, when Georg Bredig found that ethylene oxide is not an electrolyte. That it differed from other ethers — particularly by its propensity to engage in the addition reactions typical of unsaturated compounds — had long been a matter of debate. The heterocyclic triangular structure of ethylene oxide was proposed by 1868 or earlier. Wurtz's 1859 synthesis long remained the only method of preparing ethylene oxide, despite numerous attempts, including by Wurtz himself, to produce ethylene oxide directly from ethylene. Only in 1931 did French chemist Theodore Lefort develop a method of direct oxidation of ethylene in the presence of silver catalyst. Since 1940, almost all industrial production of ethylene oxide has relied on this process. Sterilization by ethylene oxide for the preservation of spices was patented in 1938 by the American chemist Lloyd Hall. Ethylene oxide achieved industrial importance during World War I as a precursor to both the coolant ethylene glycol and the chemical weapon mustard gas.
Molecular structure and properties
The epoxy cycle of ethylene oxide is an almost regular triangle with bond angles of about 60° and a significant angular strain corresponding to the energy of 105 kJ/mol. For comparison, in alcohols the C–O–H angle is about 110°; in ethers, the C–O–C angle is 120°. The moment of inertia about each of the principal axes are IA = 32.921×10−40 g·cm2, IB = 37.926×10−40 g·cm2 and IC = 59.510×10−40 g·cm2. The relative instability of the carbon-oxygen bonds in the molecule is revealed by the comparison in the table of the energy required to break two C–O bonds in the ethylene oxide or one C–O bond in ethanol and dimethyl ether:
This instability correlates with its high reactivity, explaining the ease of its ring-opening reactions (see § Chemical properties).
Physical properties Ethylene oxide is a colorless gas at 25 °C (77 °F) and is a mobile liquid at 0 °C (32 °F) – viscosity of liquid ethylene oxide at 0 °C is about 5.5 times lower than that of water. The gas has a characteristic sweet odor of ether, noticeable when its concentration in air exceeds 500 ppm. Ethylene oxide is readily soluble in water, ethanol, diethyl ether, and many organic solvents. Main thermodynamical constants are:
The surface tension of liquid ethylene oxide, at the interface with its own vapor, is 35.8 mJ/m2 (0.00079 cal/sq ft) at −50.1 °C (−58.2 °F) and 27.6 mJ/m2 (0.00061 cal/sq ft) at −0.1 °C (31.8 °F). The boiling point increases with the vapor pressure as follows: 57.7 °C (135.9 °F) (2 atm (200 kPa; 29 psi)), 83.6 °C (182.5 °F) (5 atm (510 kPa; 73 psi)), and 114.0 °C (237.2 °F) (10 atm (1,000 kPa; 150 psi)). Viscosity decreases with temperature with the values of 0.577 kPa·s at −49.8 °C (−57.6 °F), 0.488 kPa·s at −38.2 °C (−36.8 °F), 0.394 kPa·s at −21.0 °C (−5.8 °F), and 0.320 kPa·s at 0 °C (32 °F). Between −91 and 10.5 °C (−131.8 and 50.9 °F), vapor pressure p (in mmHg) varies with temperature (T in °C) as
lg p = 6.251 − 1115.1 244.14 + T {\displaystyle \lg p=6.251-{\frac {1115.1}{244.14+T}}} .
*N/A – data not available.
*N/A – data not available.
Chemical properties Ethylene oxide readily reacts with diverse compounds with opening of the ring. Its typical reactions are with nucleophiles which proceed via the SN2 mechanism both in acidic (weak nucleophiles: water, alcohols) and alkaline media (strong nucleophiles: OH−, RO−, NH3, RNH2, RR'NH, etc.). The general reaction scheme is
and more specific reactions are described below.
Addition of water and alcohols Aqueous solutions of ethylene oxide are rather stable and can exist for a long time without any noticeable chemical reaction. However adding a small amount of acid, such as strongly diluted sulfuric acid, immediately leads to the formation of ethylene glycol, even at room temperature:
(CH2CH2)O + H2O → HO–CH2CH2–OH The reaction also occurs in the gas phase, in the presence of a phosphoric acid salt as a catalyst. The reaction is usually carried out at about 60 °C (140 °F) with a large excess of water, in order to prevent the reaction of the formed ethylene glycol with ethylene oxide that would form di- and triethylene glycol:
2 (CH2CH2)O + H2O → HO–CH2CH2–O–CH2CH2–OH 3 (CH2CH2)O + H2O → HO–CH2CH2–O–CH2CH2–O–CH2CH2–OH The use of alkaline catalysts may lead to the formation of polyethylene glycol:
n (CH2CH2)O + H2O → HO–(–CH2CH2–O–)n–H Reactions with alcohols proceed similarly yielding ethylene glycol ethers:
(CH2CH2)O + C2H5OH → HO–CH2CH2–OC2H5 2 (CH2CH2)O + C2H5OH → HO–CH2CH2–O–CH2CH2–OC2H5 Reactions with lower alcohols occur less actively than with water and require more severe conditions, such as heating to 160 °C (320 °F) and pressurizing to 3 MPa (440 psi) and adding an acid or alkali catalyst. Reactions of ethylene oxide with fatty alcohols proceed in the presence of sodium metal, sodium hydroxide, or boron trifluoride and are used for the synthesis of surfactants.
Addition of carboxylic acids and their derivatives Reactions of ethylene oxide with carboxylic acids in the presence of a catalyst results in glycol mono- and diesters:
(CH2CH2)O + CH3CO2H → HOCH2CH2–O2CCH3 (CH2CH2)O + (CH3CO)2O → CH3CO2CH2CH2O2CCH3 The addition of acid amides proceeds similarly:
(CH2CH2)O + CH3CONH2 → HOCH2CH2NHC(O)CH3 Addition of ethylene oxide to higher carboxylic acids is carried out at elevated temperatures (typically 140–180 °C (284–356 °F)) and pressure (0.3–0.5 MPa (44–73 psi)) in an inert atmosphere, in presence of an alkaline catalyst (concentration 0.01–2%), such as hydroxide or carbonate of sodium or potassium. The carboxylate ion acts as nucleophile in the reaction:
(CH2CH2)O + RCO2− → RCO2CH2CH2O− RCO2CH2CH2O− + RCO2H → RCO2CH2CH2OH + RCO2−
Adding ammonia and amines Ethylene oxide reacts with ammonia forming a mixture of mono-, di-, and tri- ethanolamines. The reaction is stimulated by adding a small amount of water.
(CH2CH2)O + NH3 → HO–CH2CH2–NH2 2 (CH2CH2)O + NH3 → (HO–CH2CH2)2NH 3 (CH2CH2)O + NH3 → (HO–CH2CH2)3N Similarly proceed the reactions with primary and secondary amines:
(CH2CH2)O + RNH2 → HO–CH2CH2–NHR Dialkylamino ethanols can further react with ethylene oxide, forming amino polyethylene glycols:
n (CH2CH2)O + R2NCH2CH2OH → R2NCH2CH2O–(–CH2CH2O–)n–H Trimethylamine reacts with ethylene oxide in the presence of water, forming choline:
(CH2CH2)O + (CH3)3N + H2O → [HOCH2CH2N (CH3)3]+OH− Aromatic primary and secondary amines also react with ethylene oxide, forming the corresponding arylamino alcohols.
Halide addition Ethylene oxide readily reacts with aqueous solutions of hydrochloric, hydrobromic, and hydroiodic acids to form halohydrins. The reaction occurs easier with the last two acids:
(CH2CH2)O + HCl → HO–CH2CH2–Cl The reaction with these acids competes with the acid-catalyzed hydration of ethylene oxide; therefore, there is always a by-product of ethylene glycol with an admixture of diethylene glycol. For a cleaner product, the reaction is conducted in the gas phase or in an organic solvent. Ethylene fluorohydrin is obtained differently, by boiling hydrogen fluoride with a 5–6% solution of ethylene oxide in diethyl ether. The ether normally has a water content of 1.5–2%; in absence of water, ethylene oxide polymerizes. Halohydrins can also be obtained by passing ethylene oxide through aqueous solutions of metal halides:
2 (CH2CH2)O + CuCl2 + 2 H2O → 2 HO–CH2CH2–Cl + Cu(OH)2↓
Metalorganic addition Interaction of ethylene oxide with organomagnesium compounds, which are Grignard reagents, can be regarded as nucleophilic substitution influenced by carbanion organometallic compounds. The final product of the reaction is a primary alcohol:
( CH 2 CH 2 ) O
+ RMgBr ⟶ R − CH 2 CH 2 − OMgBr → H 2 O R − CH 2 CH 2 − OH primary alcohol {\displaystyle {\ce {(CH2CH2)O{}+RMgBr->R-CH2CH2-OMgBr->[{\ce {H2O}}]{\overset {primary~alcohol}{R-CH2CH2-OH}}}}}
Similar mechanism is valid for other organometallic compounds, such as alkyl lithium:
( CH 2 CH 2 ) O
+ RLi alkyl lithium ⟶ R − CH 2 CH 2 − OLi → H 2 O R − CH 2 CH 2 − OH {\displaystyle {\ce {(CH2CH2)O{}+{\overset {alkyl~lithium}{RLi}}->R-CH2CH2-OLi->[{\ce {H2O}}]R-CH2CH2-OH}}}
Other addition reactions
Addition of hydrogen cyanide Ethylene oxide easily reacts with hydrogen cyanide forming ethylene cyanohydrin:
(CH2CH2)O + HCN → HO–CH2CH2–CN A slightly chilled (10–20 °C) aqueous solution of calcium cyanide can be used instead of HCN:
2 (CH2CH2)O + Ca(CN)2 + 2 H2O → 2 HO–CH2CH2–CN + Ca(OH)2 Ethylene cyanohydrin easily loses water, producing acrylonitrile:
HO–CH2CH2–CN → CH2=CH–CN + H2O
Addition of hydrogen sulfide and mercaptans When reacting with the hydrogen sulfide, ethylene oxide forms 2-mercaptoethanol and thiodiglycol, and with alkylmercaptans it produces 2-alkyl mercaptoethanol:
(CH2CH2)O + H2S → HO–CH2CH2–HS 2 (CH2CH2)O + H2S → (HO–CH2CH2)2S (CH2CH2)O + RHS → HO–CH2CH2–SR The excess of ethylene oxide with an aqueous solution of hydrogen sulfide leads to the tris-(hydroxyethyl) sulfonyl hydroxide:
3 (CH2CH2)O + H2S → [(HO–CH2CH2)3S+]OH−
Addition of nitrous and nitric acids Reaction of ethylene oxide with aqueous solutions of barium nitrite, calcium nitrite, magnesium nitrite, zinc nitrite, or sodium nitrite leads to the formation of 2-nitroethanol:
2 (CH2CH2)O + Ca(NO2)2 + 2 H2O → 2 HO–CH2CH2–NO2 + Ca(OH)2 With nitric acid, ethylene oxide forms mono- and dinitroglycols:
( CH 2 CH 2 ) O
+ HNO 3 nitric acid ⟶ HO − CH 2 CH 2 − ONO 2 → − H 2 O + HNO 3 O 2 NO − CH 2 CH 2 − ONO 2 {\displaystyle {\ce {(CH2CH2)O{}+{\overset {nitric \atop acid}{HNO3}}->HO-CH2CH2-ONO2->[{\ce {+HNO3}}][{\ce {-H2O}}]O2NO-CH2CH2-ONO_{2}}}}
Reaction with compounds containing active methylene groups In the presence of alkoxides, reactions of ethylene oxide with compounds containing active methylene group leads to the formation of butyrolactones:
Alkylation of aromatic compounds Ethylene oxide enters into the Friedel–Crafts reaction with benzene to form phenethyl alcohol:
Styrene can be obtained in one stage if this reaction is conducted at elevated temperatures (315–440 °C (599–824 °F)) and pressures (0.35–0.7 MPa (51–102 psi)), in presence of an aluminosilicate catalyst.
Synthesis of crown ethers A series of polynomial heterocyclic compounds, known as crown ethers, can be synthesized with ethylene oxide. One method is the cationic cyclopolymerization of ethylene oxide, limiting the size of the formed cycle:
n (CH2CH2)O → (–CH2CH2–O–)n To suppress the formation of other linear polymers the reaction is carried out in a highly dilute solution. Reaction of ethylene oxide with sulfur dioxide in the presence of caesium salts leads to the formation of an 11-membered heterocyclic compound which has the complexing properties of crown ethers:
Isomerization When heated to about 400 °C (750 °F), or to 150–300 °C (300–570 °F) in the presence of a catalyst (Al2O3, H3PO4, etc.), ethylene oxide isomerizes into acetaldehyde:
( CH 2 CH 2 ) O → Al 2 O 3 200 ∘ C CH 3 CHO acetaldehyde {\displaystyle {\ce {(CH2CH2)O->[{\ce {200^{\circ }C}}][{\ce {Al2O3}}]{\overset {acetaldehyde}{CH3CHO}}}}}
The radical mechanism was proposed to explain this reaction in the gas phase; it comprises the following stages:
In reaction (3), M refers to the wall of the reaction vessel or to a heterogeneous catalyst. The moiety CH3CHO* represents a short-lived (lifetime of 10−8.5 seconds), activated molecule of acetaldehyde. Its excess energy is about 355.6 kJ/mol, which exceeds by 29.3 kJ/mol the binding energy of the C-C bond in acetaldehyde. In absence of a catalyst, the thermal isomerization of ethylene oxide is never selective and apart from acetaldehyde yields significant amount of by-products (see section Thermal decomposition).
Reduction reaction Ethylene oxide can be hydrogenated into ethanol in the presence of a catalyst, such as nickel, platinum, palladium, boranes, lithium aluminium hydride, and some other hydrides.
( CH 2 CH 2 ) O
+ H 2 → 80 ∘ C Ni , Pt , Pd , BH 3 , LiAlH 4 or other hydrides C 2 H 5 OH ethanol {\displaystyle {\ce {(CH2CH2)O{}+H2->[{\ce {Ni,Pt,Pd,BH3,LiAlH4}}{\text{ or other hydrides}}][{\ce {80^{\circ }C}}]{\underset {ethanol}{C2H5OH}}}}}
Conversely, with some other catalysts, ethylene oxide may be reduced by hydrogen to ethylene with the yield up to 70%. The reduction catalysts include mixtures of zinc dust and acetic acid, of lithium aluminium hydride with titanium trichloride (the reducing agent is actually titanium dichloride, formed by the reaction between LiAlH4 and TiCl3) and of iron(III) chloride with butyllithium in tetrahydrofuran.
( CH 2 CH 2 ) O
+ H 2 → Zn + CH 3 COOH CH 2 = CH 2 ethylene + H 2 O {\displaystyle {\ce {(CH2CH2)O{}+ H2 ->[{\ce {{Zn}+ CH3COOH}}] {\underset {ethylene}{CH2=CH2}}+ H2O}}}
Oxidation Ethylene oxide can further be oxidized, depending on the conditions, to glycolic acid or carbon dioxide:
( CH 2 CH 2 ) O
+ O 2 → AgNO 3 HOCH 2 CO 2 H glycolic acid {\displaystyle {\ce {(CH2CH2)O{}+O2->[{\ce {AgNO3}}]{\overset {glycolic\ acid}{HOCH2CO2H}}}}}
Deep gas-phase reactor oxidation of ethylene oxide at 800–1,000 K (527–727 °C; 980–1,340 °F) and a pressure of 0.1–1 MPa (15–145 psi) yields a complex mixture of products containing O2, H2, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H6, C3H8, and CH3CHO.
Dimerization In the presence of acid catalysts, ethylene oxide dimerizes to afford dioxane:
The reaction mechanism is as follows:
The dimerization reaction is unselective. By-products include acetaldehyde (due to isomerization). The selectivity and speed of dimerization can be increased by adding a catalyst, such as platinum, platinum-palladium, or iodine with sulfolane. 2-methyl-1,3-dioxolane is formed as a side product in the last case.
Polymerization Liquid ethylene oxide can form polyethylene glycols. The polymerization can proceed via radical and ionic mechanisms, but only the latter has a wide practical application. Cationic polymerization of ethylene oxide is assisted by protic acids (HClO4, HCl), Lewis acids (SnCl4, BF3, etc.), organometallic compounds, or more complex reagents:
n ( CH 2 CH 2 ) O → SnCl 4 ( CH 2 CH 2 − O − ) n ⏞ polyethyleneglycol {\displaystyle n{\ce {(CH2CH2)O ->[{\ce {SnCl4}}]}}\ \overbrace {{\ce {(CH2CH2-O-)}}_{n}} ^{{\ce {polyethyleneglycol}}}}
The reaction mechanism is as follows. At the first stage, the catalyst (MXm) is initiated by alkyl-or acylhalogen or by compounds with active hydrogen atoms, usually water, alcohol, or glycol:
MXm + ROH → MXmRO−H+ The resulting active complex reacts with ethylene oxide via the SN2 mechanism:
(CH2CH2)O + MXmRO−H+ → (CH2CH2)O•••H+O−RMXm (CH2CH2)O•••H+ O−RMXm → HO–CH2CH2+ + MXmRO−2 HO–CH2CH2+ + n (CH2CH2)O → HO–CH2CH2–(O–CH2CH2)n+ The chain breaks as
HO–CH2CH2–(O–CH2CH2)n+ + MXmRO− → HO–CH2CH2–(O–CH2CH2)n–OR + MXm H(O–CH2CH2)n–O–CH2–CH2+ + MXmRO− → H(O–CH2CH2)n–O–CH=CH2 + MXm + ROH Anionic polymerization of ethylene oxide is assisted by bases, such as alkoxides, hydroxides, carbonates, or other compounds of alkali or alkaline earth metals. The reaction mechanism is as follows:
(CH2CH2)O + RONa → RO–CH2CH2–O−Na+ RO–CH2CH2–O−Na+ + n (CH2CH2)O → RO–(CH2CH2–O)n–CH2CH2–O−Na+ RO–(CH2CH2–O)n–CH2CH2–O−Na+ → RO–(CH2CH2–O)n–CH=CH2 + NaOH RO–(CH2CH2–O)n–CH2CH2–O−Na+ + H2O → RO–(CH2CH2–O)(n+1)OH + NaOH
Thermal decomposition Ethylene oxide is relatively stable to heating – in the absence of a catalyst, it does not dissociate up to 300 °C (572 °F), and only above 570 °C (1,058 °F) there is a major exothermic decomposition, which proceeds through the radical mechanism. The first stage involves isomerization, however high temperature accelerates the radical processes. They result in a gas mixture containing acetaldehyde, ethane, ethyl, methane, hydrogen, carbon dioxide, ketene, and formaldehyde. High-temperature pyrolysis (830–1,200 K (557–927 °C; 1,034–1,700 °F)) at elevated pressure in an inert atmosphere leads to a more complex composition of the gas mixture, which also contains acetylene and propane. Contrary to the isomerization, initiation of the chain occurs mainly as follows:
(CH2CH2)O → •CH2CH2O• → CH2O + CH2: When carrying the thermal decomposition of ethylene oxide in the presence of transition metal compounds as catalysts, it is possible not only to reduce its temperature, but also to have ethyl as the main product, that is to reverse the ethylene oxide synthesis reaction.
Other reactions Thiocyanate ions or thiourea transform ethylene oxide into thiirane (ethylene sulfide):
(CH2CH2)O + (NH2)2C=S → (CH2CH2)S + (NH2)2C=O
Reaction of phosphorus pentachloride with ethylene oxide produces ethylene dichloride:
(CH2CH2)O + PCl5 → Cl–CH2CH2–Cl + POCl3 Other dichloro derivatives of ethylene oxide can be obtained by combined action of sulfuryl chloride (SOCl2) and pyridine and of triphenylphosphine and carbon tetrachloride. Phosphorus trichloride reacts with ethylene oxide forming chloroethyl esters of phosphorous acid:
(CH2CH2)O + PCl3 → Cl–CH2CH2–OPCl2 2 (CH2CH2)O + PCl3 → (Cl–CH2CH2–O)2PCl 3 (CH2CH2)O + PCl3 → Cl–CH2CH2–O)3P The reaction product of ethylene oxide with acyl chlorides in the presence of sodium iodide is a complex iodoethyl ester:
(CH2CH2)O + RCOCl + NaI → RC(O)–OCH2CH2–I + NaCl Heating ethylene oxide to 100 °C with carbon dioxide, in a non-polar solvent in the presence of bis-(triphenylphosphine)-nickel(0) results in ethylene carbonate:
In industry, a similar reaction is carried out at high pressure and temperature in the presence of quaternary ammonium or phosphonium salts as a catalyst. Reaction of ethylene oxide with formaldehyde at 80–150 °C in the presence of a catalyst leads to the formation of 1,3-dioxolane:
Substituting formaldehyde by other aldehydes or ketones results in a 2-substituted 1,3-dioxolane (yield: 70–85%, catalyst: tetraethylammonium bromide). Catalytic hydroformylation of ethylene oxide gives hydroxypropanal which can be hydrogenated to propane-1,3-diol:
( CH 2 CH 2 ) O + CO + H 2 ⟶ CHO − CH 2 CH 2 − OH → + H 2 HO − CH 2 CH 2 CH 2 − OH {\displaystyle {\ce {(CH2CH2)O + CO + H2 -> CHO-CH2CH2-OH ->[{\ce {+H2}}] HO-CH2CH2CH2-OH}}}
Laboratory synthesis
Dehydrochlorination of ethylene and its derivatives Dehydrochlorination of 2-chloroethanol, developed by Wurtz in 1859, remains a common laboratory route to ethylene oxide:
Cl − CH 2 CH 2 − OH + NaOH ⟶ ( CH 2 CH 2 ) O + NaCl + H 2 O {\displaystyle {\ce {Cl-CH2CH2-OH + NaOH -> (CH2CH2)O + NaCl + H2O}}}
The reaction is carried out at elevated temperature, and beside sodium hydroxide or potassium hydroxide, calcium hydroxide, barium hydroxide, magnesium hydroxide, or carbonates of alkali or alkaline earth metals can be used. With a high yield (90%) ethylene oxide can be produced by treating calcium oxide with ethyl hypochlorite; substituting calcium by other alkaline earth metals reduces the reaction yield:
2 CH 3 CH 2 − OCl + CaO ⟶ 2 ( CH 2 CH 2 ) O + CaCl 2 + H 2 O {\displaystyle {\ce {2 CH3CH2-OCl + CaO -> 2 (CH2CH2)O + CaCl2 + H2O}}}
Direct oxidation of ethylene by peroxy acids Ethylene can be directly oxidized into ethylene oxide using peroxy acids, for example, peroxybenzoic or meta-chloro-peroxybenzoic acid:
Oxidation by peroxy acids is efficient for higher alkenes, but not for ethylene. The above reaction is slow and has low yield, therefore it is not used in the industry.
Other preparative methods Other synthesis methods include reaction of diiodo ethane with silver oxide:
I − CH 2 CH 2 − I + Ag 2 O ⟶ ( CH 2 CH 2 ) O + 2 AgI {\displaystyle {\ce {I-CH2CH2-I + Ag2O -> (CH2CH2)O + 2AgI}}}
and decomposition of ethylene carbonate at 200–210 °C (392–410 °F) in the presence of hexachloroethane:
Industrial synthesis
History Commercial production of ethylene oxide dates back to 1914 wh