Ethylene oxide

Formula: C₂H₄O
Molecular weight: 44.0526
IUPAC Standard InChI: InChI=1S/C2H4O/c1-2-3-1/h1-2H2
IUPAC Standard InChIKey: IAYPIBMASNFSPL-UHFFFAOYSA-N
CAS Registry Number: 75-21-8
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Other names: Oxirane; Dihydrooxirene; Dimethylene oxide; Epoxyethane; Ethene oxide; ETO; Oxacyclopropane; Oxane; Oxidoethane; Oxirene, dihydro-; Oxyfume; Oxyfume 12; T-Gas; 1,2-Epoxyethane; Aethylenoxid; Amprolene; Anprolene; Anproline; ENT-26263; E.O.; 1,2-Epoxyaethan; Ethyleenoxide; Etylenu tlenek; FEMA No. 2433; Merpol; NCI-C50088; α,β-Oxidoethane; Oxiraan; Oxiran; Rcra waste number U115; Sterilizing gas ethylene oxide 100%; UN 1040; Qazi-ketcham
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Gas phase thermochemistry data

Go To: Top, Condensed phase thermochemistry data, Gas phase ion energetics data, References, Notes

Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-52.64	kJ/mol	Review	Chase, 1998	Data last reviewed in September, 1965
Δ_fH°_gas	-52.63 ± 0.63	kJ/mol	Cm	Pell and Pilcher, 1965	ALS
Δ_fH°_gas	-70.2	kJ/mol	N/A	Moureu and Dode, 1937	Value computed using Δ_fH_liquid° value of -95.7±1.3 kj/mol from Moureu and Dode, 1937 and Δ_vapH° value of 25.51 kj/mol from missing citation.; DRB
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_gas	-1306.0 ± 0.59	kJ/mol	Cm	Pell and Pilcher, 1965	Corresponding Δ_fHº_gas = -52.63 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_gas	-1307.7 ± 0.84	kJ/mol	Ccb	Crog and Hunt, 1942	Corresponding Δ_fHº_gas = -50.96 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	243.00	J/mol*K	Review	Chase, 1998	Data last reviewed in September, 1965

Constant pressure heat capacity of gas

C_p,gas (J/mol*K)	Temperature (K)	Reference	Comment
33.26	50.	Dorofeeva O.V., 1992	p=1 bar. Selected values are in good agreement with other statistically calculated values [ Godnev I., 1948, Gunthard H., 1948, Kobe K.A., 1950, Sundaram S., 1963, Ramasamy R., 1978, Chao J., 1986].; GT
33.28	100.
33.82	150.
36.19	200.
43.71	273.15
47.0 ± 1.0	298.15
47.29	300.
61.66	400.
74.89	500.
85.97	600.
95.14	700.
102.81	800.
109.32	900.
114.89	1000.
119.67	1100.
123.79	1200.
127.36	1300.
130.45	1400.
133.14	1500.

Constant pressure heat capacity of gas

C_p,gas (J/mol*K)	Temperature (K)	Reference	Comment
49.37	307.18	Kistiakowsky G.B., 1940	GT
53.51	337.04
58.41	371.23

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
C_p = heat capacity (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.

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Temperature (K)	298. to 1200.	1200. to 6000.
A	-23.25802	131.3483
B	275.6997	13.80594
C	-188.9729	-2.645062
D	51.03350	0.175820
E	0.386930	-30.03639
F	-55.09156	-158.3795
G	142.7777	313.4276
H	-52.63514	-52.63514
Reference	Chase, 1998	Chase, 1998
Comment	Data last reviewed in September, 1965	Data last reviewed in September, 1965

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References, Notes

Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_liquid	-95.7 ± 1.3	kJ/mol	Ccb	Moureu and Dode, 1937	Reanalyzed by Cox and Pilcher, 1970, Original value = -95.4 kJ/mol; ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-1262.9 ± 1.3	kJ/mol	Ccb	Moureu and Dode, 1937	Reanalyzed by Cox and Pilcher, 1970, Original value = -1264. kJ/mol; Corresponding Δ_fHº_liquid = -95.73 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	149.45	J/mol*K	N/A	Giauque and Gordon, 1949	DH

Constant pressure heat capacity of liquid

C_p,liquid (J/mol*K)	Temperature (K)	Reference	Comment
86.90	285.	Giauque and Gordon, 1949	T = 15 to 283 K.; DH

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, References, Notes

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C₂H₄O⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	10.56 ± 0.01	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	774.2	kJ/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	745.3	kJ/mol	N/A	Hunter and Lias, 1998	HL

Ionization energy determinations

IE (eV)	Method	Reference	Comment
10.15 ± 0.05	EI	Holmes and Lossing, 1991	LL
10.4 ± 0.1	PE	Aue, Webb, et al., 1980	LLK
10.4	PE	Aue and Bowers, 1979	LLK
10.57	EI	Holmes, Terlouw, et al., 1976	LLK
10.6 ± 0.1	PI	Corderman, LeBreton, et al., 1976	LLK
10.560	PE	Corderman, LeBreton, et al., 1976	LLK
10.56 ± 0.01	PI	Krassig, Reinke, et al., 1974	LLK
10.57	PE	Basch, Robin, et al., 1969	RDSH
10.566	S	Lowrey and Watanabe, 1958	RDSH
10.57 ± 0.01	PI	Watanabe, 1957	RDSH
10.57	EI	Vorob'ev, Furlei, et al., 1989	Vertical value; LL
10.57	PIPECO	Johnson, Powis, et al., 1982	Vertical value; LBLHLM
10.57	PE	Bieri, Asbrink, et al., 1982	Vertical value; LBLHLM
10.57	PE	Kimura, Katsumata, et al., 1981	Vertical value; LLK
10.568	PE	Aue, Webb, et al., 1975	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
CH⁺	22.8 ± 0.4	?	EI	Gallegos and Kiser, 1961	RDSH
CHO⁺	11.54 ± 0.03	CH₃	PI	Krassig, Reinke, et al., 1974	LLK
CHO⁺	12.2 ± 0.1	CH₃	EI	Gallegos and Kiser, 1961	RDSH
CH₂⁺	14.66 ± 0.09	?	PI	Krassig, Reinke, et al., 1974	LLK
CH₂⁺	16.5 ± 0.4	?	EI	Gallegos and Kiser, 1961	RDSH
CH₃⁺	13.06 ± 0.05	CO+H	PI	Krassig, Reinke, et al., 1974	LLK
CH₃⁺	14.3 ± 0.2	?	EI	Gallegos and Kiser, 1961	RDSH
CH₄⁺	11.79 ± 0.03	CO	PI	Krassig, Reinke, et al., 1974	LLK
CH₄⁺	12.3 ± 0.2	CO	EI	Gallegos and Kiser, 1961	RDSH
CO⁺	12.6 ± 0.4	CH₄	EI	Gallegos and Kiser, 1961	RDSH
C₂H⁺	24.0 ± 0.3	?	EI	Gallegos and Kiser, 1961	RDSH
C₂H₂⁺	15.7 ± 0.3	H₂O?	EI	Gallegos and Kiser, 1961	RDSH
C₂H₂O⁺	13.07 ± 0.05	H₂?	PI	Krassig, Reinke, et al., 1974	LLK
C₂H₂O⁺	14.0 ± 0.3	2H?	EI	Gallegos and Kiser, 1961	RDSH
C₂H₃⁺	12.92 ± 0.08	OH	PI	Krassig, Reinke, et al., 1974	LLK
C₂H₃⁺	14.3 ± 0.2	OH	EI	Gallegos and Kiser, 1961	RDSH
C₂H₃O⁺	11.53 ± 0.05	H	EI	Burgers and Holmes, 1982	LBLHLM
C₂H₃O⁺	11.62 ± 0.05	H	PI	Krassig, Reinke, et al., 1974	LLK
C₂H₃O⁺	12.1 ± 0.2	H	EI	Gallegos and Kiser, 1961	RDSH

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Gas phase ion energetics data, Notes

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Pell and Pilcher, 1965
Pell, A.S.; Pilcher, G., Measurements of heats of combustion by flame calorimetry. Part 3.-Ethylene oxide, trimethylene oxide, tetrahydrofuran and tetrahydropy, Trans. Faraday Soc., 1965, 61, 71-77. [all data]

Moureu and Dode, 1937
Moureu, H.; Dode, M., Chaleurs de formation de l'oxyde d'ethylene, de l'ethanediol et de quelques homologues, Bull. Soc. Chim. France, 1937, 4, 637-647. [all data]

Crog and Hunt, 1942
Crog, R.S.; Hunt, H., Heats of combustion. II. The heats of combustion of ethyl methyl ketone and ethylene oxide, J. Phys. Chem., 1942, 46, 1162-1163. [all data]

Dorofeeva O.V., 1992
Dorofeeva O.V., Ideal gas thermodynamic properties of oxygen heterocyclic compounds. Part 1. Three-membered, four-membered and five-membered rings, Thermochim. Acta, 1992, 194, 9-46. [all data]

Godnev I., 1948
Godnev I., Thermodynamic functions of ethylene oxide, Zh. Fiz. Khim., 1948, 22, 801-803. [all data]

Gunthard H., 1948
Gunthard H., Thermodynamic properties of ethylene oxide, Helv. Chim. Acta, 1948, 31, 2128-2132. [all data]

Kobe K.A., 1950
Kobe K.A., Thermochemistry for the petrochemical industry. XIII. Some oxygenated hydrocarbons C1 and C2, Petrol. Refiner, 1950, 29 (9), 135-138. [all data]

Sundaram S., 1963
Sundaram S., Thermodynamic functions of some propellants, Z. Phys. Chem. (Frankfurt), 1963, 36, 376-377. [all data]

Ramasamy R., 1978
Ramasamy R., Centrifugal distortion constants and thermodynamic functions of ethylene oxide, ethylene oxide-d4, and ethylene sulfide, Curr. Sci., 1978, 47, 668-669. [all data]

Chao J., 1986
Chao J., Thermodynamic properties of key organic oxygen compounds in the carbon range C1 to C4. Part 2. Ideal gas properties, J. Phys. Chem. Ref. Data, 1986, 15, 1369-1436. [all data]

Kistiakowsky G.B., 1940
Kistiakowsky G.B., Gaseous heat capacities. III, J. Chem. Phys., 1940, 8, 618-622. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Giauque and Gordon, 1949
Giauque, W.F.; Gordon, J., The entropy of ethylene oxide. Heat capacity from 14 to 285K. Vapor pressure. Heats of fusion and vaporization, J. Am. Chem. Soc., 1949, 71, 2176-2181. [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Holmes and Lossing, 1991
Holmes, J.L.; Lossing, F.P., Ionization energies of homologous organic compounds and correlation with molecular size, Org. Mass Spectrom., 1991, 26, 537. [all data]

Aue, Webb, et al., 1980
Aue, D.H.; Webb, H.M.; Davidson, W.R.; Vidal, M.; Bowers, M.T.; Goldwhite, H.; Vertal, L.E.; Douglas, J.E.; Kollman, P.A.; Kenyon, G.L., Proton affinities photoelectron spectra of three-membered-ring J. Heterocycl. Chem., J. Am. Chem. Soc., 1980, 102, 5151. [all data]

Aue and Bowers, 1979
Aue, D.H.; Bowers, M.T., Chapter 9. Stabilities of positive ions from equilibrium gas phase basicity measurements in Ions Chemistry,, ed. M.T. Bowers, 1979. [all data]

Holmes, Terlouw, et al., 1976
Holmes, J.L.; Terlouw, J.K.; Lossing, F.P., The thermochemistry of C₂H₄O⁺ ions, J. Phys. Chem., 1976, 80, 2860. [all data]

Corderman, LeBreton, et al., 1976
Corderman, R.R.; LeBreton, P.R.; Buttrill, S.E., Jr.; Williamson, A.D.; Beauchamp, J.L., Photoionization and ion cyclotron resonance studies of the ion chemistry of ethylene oxide, J. Chem. Phys., 1976, 65, 4929. [all data]

Krassig, Reinke, et al., 1974
Krassig, R.; Reinke, D.; Baumgartel, H., Photo-reaktionen kleiner organischer molekule II. Die photoionenspektren der Isomeren propylen-cyclopropan und acetaldehyd-athylenoxyd, Ber. Bunsen-Ges. Phys. Chem., 1974, 78, 425. [all data]

Basch, Robin, et al., 1969
Basch, H.; Robin, M.B.; Kuebler, N.A.; Baker, C.; Turner, D.W., Optical and photoelectron spectra of small rings. III. The saturated three-membered rings, J. Chem. Phys., 1969, 51, 52. [all data]

Lowrey and Watanabe, 1958
Lowrey, A., III; Watanabe, K., Absorption and ionization coefficients of ethylene oxide, J. Chem. Phys., 1958, 28, 208. [all data]

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Vorob'ev, Furlei, et al., 1989
Vorob'ev, A.S.; Furlei, I.I.; Sultanov, A.S.; Khvostenko, V.I.; Leplyanin, G.V.; Derzhinskii, A.R.; Tolstikov, G.A., Mass spectrometry of reasonance capture of electrons and photoelectron spectroscopy of molecules of ethylene oxide, ethylene sulfide, and their derivatives, Bull. Acad. Sci. USSR, Div. Chem. Sci., 1989, 1388. [all data]

Johnson, Powis, et al., 1982
Johnson, K.; Powis, I.; Danby, C.J., A photoelectron-photoion coincidence study of acetaldehyde and ethylene oxide molecular ions, Chem. Phys., 1982, 70, 329. [all data]

Bieri, Asbrink, et al., 1982
Bieri, G.; Asbrink, L.; Von Niessen, W., 30.4-nm He(II) photoelectron spectra of organic molecules, J. Electron Spectrosc. Relat. Phenom., 1982, 27, 129. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Aue, Webb, et al., 1975
Aue, D.H.; Webb, H.M.; Bowers, M.T., Proton affinities, ionization potentials, and hydrogen affinities of nitrogen and oxygen bases. Hybridization effects, J. Am. Chem. Soc., 1975, 97, 4137. [all data]

Gallegos and Kiser, 1961
Gallegos, E.J.; Kiser, R.W., Electron impact spectroscopy of ethylene oxide and propylene oxide, J. Am. Chem. Soc., 1961, 83, 773. [all data]

Burgers and Holmes, 1982
Burgers, P.C.; Holmes, J.L., Metastable ion studies. XIII. The measurement of appearance energies of metastable peaks, Org. Mass Spectrom., 1982, 17, 123. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Gas phase ion energetics data, References

Symbols used in this document:

AE	Appearance energy
C_p,gas	Constant pressure heat capacity of gas
C_p,liquid	Constant pressure heat capacity of liquid
IE (evaluated)	Recommended ionization energy
S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
S°_liquid	Entropy of liquid at standard conditions
Δ_cH°_gas	Enthalpy of combustion of gas at standard conditions
Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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