2-Butyne
- Formula: C4H6
- Molecular weight: 54.0904
- IUPAC Standard InChIKey: XNMQEEKYCVKGBD-UHFFFAOYSA-N
- CAS Registry Number: 503-17-3
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Other names: But-2-yne; Dimethylacetylene; CH3C≡CCH3; Crotonylene; UN 1144
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Condensed phase thermochemistry data
Go To: Top, Phase change data, Gas phase ion energetics data, Mass spectrum (electron ionization), References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: Eugene S. Domalski and Elizabeth D. Hearing
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
S°liquid | 195.10 | J/mol*K | N/A | Yost, Osborne, et al., 1941 | Extrapolated from 291.0 K. Anomalous heat capacity between 145 and 160 K. S obtained from total energy divided by average temperature. |
Constant pressure heat capacity of liquid
Cp,liquid (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
124.14 | 290. | Yost, Osborne, et al., 1941 | T = 15 to 290 K. |
Phase change data
Go To: Top, Condensed phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos
DH - Eugene S. Domalski and Elizabeth D. Hearing
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Tboil | 300. ± 1. | K | AVG | N/A | Average of 23 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 240.82 | K | N/A | Pomerantz, Fookson, et al., 1954 | Uncertainty assigned by TRC = 0.2 K; TRC |
Tfus | 240.9 | K | N/A | Boord, Greenlee, et al., 1946 | Uncertainty assigned by TRC = 0.2 K; TRC |
Tfus | 240.63 | K | N/A | Boord, Greenlee, et al., 1946 | Uncertainty assigned by TRC = 0.3 K; TRC |
Tfus | 240.83 | K | N/A | Henne and Greenlee, 1945 | Uncertainty assigned by TRC = 0.1 K; TRC |
Tfus | 240.5 | K | N/A | Heisig and Davis, 1935 | Uncertainty assigned by TRC = 0.3 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 240.8 | K | N/A | Yost, Osborne, et al., 1941, 2 | Uncertainty assigned by TRC = 0.15 K; TRC |
Ttriple | 240.93 | K | N/A | Yost, Osborne, et al., 1941, 2 | Uncertainty assigned by TRC = 0.06 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ΔvapH° | 26.7 | kJ/mol | N/A | Reid, 1972 | AC |
Enthalpy of vaporization
ΔvapH (kJ/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
26.945 | 291.0 | N/A | Yost, Osborne, et al., 1941 | P = 71.46 kPa; DH |
26.945 | 291.00 | N/A | Osborne, Garner, et al., 1940 | DH |
29. | 255. | A | Stephenson and Malanowski, 1987 | Based on data from 240. to 308. K.; AC |
26.9 ± 0.3 | 291.00 | C | Yost, Osborne, et al., 1941, 3 | ALS |
26.9 ± 0.1 | 291. | C | Yost, Osborne, et al., 1941 | AC |
Entropy of vaporization
ΔvapS (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
92.59 | 291.0 | Yost, Osborne, et al., 1941 | P; DH |
92.59 | 291.00 | Osborne, Garner, et al., 1940 | DH |
Enthalpy of sublimation
ΔsubH (kJ/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
37.4 | 220. | A | Stull, 1947 | Based on data from 200. to 239. K.; AC |
Enthalpy of fusion
ΔfusH (kJ/mol) | Temperature (K) | Reference | Comment |
---|---|---|---|
9.2349 | 240.92 | Yost, Osborne, et al., 1941 | DH |
9.2328 | 240.93 | Osborne, Garner, et al., 1940 | DH |
9.25 | 240.9 | Acree, 1991 | AC |
Entropy of fusion
ΔfusS (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
38.348 | 240.92 | Yost, Osborne, et al., 1941 | DH |
38.33 | 240.93 | Osborne, Garner, et al., 1940 | DH |
Gas phase ion energetics data
Go To: Top, Condensed phase thermochemistry data, Phase change data, Mass spectrum (electron ionization), References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias
Data compiled as indicated in comments:
B - John E. Bartmess
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 C4H6+ (ion structure unspecified)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 9.58 ± 0.02 | eV | N/A | N/A | L |
Quantity | Value | Units | Method | Reference | Comment |
Proton affinity (review) | 775.8 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 745.1 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
9.59 ± 0.02 | PE | Bieri, Burger, et al., 1977 | LLK |
9.562 ± 0.005 | PE | Carlier, Dubois, et al., 1975 | LLK |
9.61 | PE | Ensslin, Bock, et al., 1974 | LLK |
9.59 | PE | Brogli, Heilbronner, et al., 1973 | LLK |
9.56 | EI | Lossing, 1972 | LLK |
9.79 | PE | Bieri and Asbrink, 1980 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
CH3+ | 17.6 ± 0.5 | ? | EI | Coats and Anderson, 1957 | RDSH |
C2H3+ | 14.7 ± 0.2 | ? | EI | Coats and Anderson, 1957 | RDSH |
C3H3+ | 11.04 | CH3 | EI | Lossing, 1972 | LLK |
C4H2+ | 16.7 ± 0.3 | ? | EI | Coats and Anderson, 1957 | RDSH |
C4H3+ | 15.1 ± 0.2 | H2+H | EI | Coats and Anderson, 1957 | RDSH |
C4H4+ | 14.0 ± 0.1 | H2 | EI | Coats and Anderson, 1957 | RDSH |
C4H5+ | 12.1 ± 0.1 | H | EI | Coats and Anderson, 1957 | RDSH |
De-protonation reactions
C4H5- + =
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 1628. ± 8.8 | kJ/mol | G+TS | Gal, Decouzon, et al., 2001 | gas phase; Acid: MeC≡CMe; B |
ΔrH° | 1628. ± 14. | kJ/mol | G+TS | N/A | gas phase; Measured vs pyridine; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 1597. ± 8.4 | kJ/mol | IMRE | Gal, Decouzon, et al., 2001 | gas phase; Acid: MeC≡CMe; B |
ΔrG° | 1596. ± 13. | kJ/mol | IMRE | N/A | gas phase; Measured vs pyridine; B |
Mass spectrum (electron ionization)
Go To: Top, Condensed phase thermochemistry data, Phase change data, Gas phase ion energetics data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
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Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
---|---|
Origin | Japan AIST/NIMC Database- Spectrum MS-IW- 744 |
NIST MS number | 227606 |
References
Go To: Top, Condensed phase thermochemistry data, Phase change data, Gas phase ion energetics data, Mass spectrum (electron ionization), Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Yost, Osborne, et al., 1941
Yost, D.M.; Osborne, D.W.; Garner, C.S.,
The heat capacity, entropy, and heats of transition, fusion, and vaporization of dimethylacetylene. Free rotation in the dimethylacetylene molecule,
J. Am. Chem. Soc., 1941, 63, 3492-3496. [all data]
Pomerantz, Fookson, et al., 1954
Pomerantz, P.; Fookson, A.; Mears, T.W.; Rothberg, S.; Howard, F.L.,
Synthesis and Physical Properties of Several Acetylenic Hydrocarbons,
J. Res. Natl. Bur. Stand. (U. S.), 1954, 52, 51. [all data]
Boord, Greenlee, et al., 1946
Boord, C.E.; Greenlee, K.W.; Perilstein, W.L.,
The Synthesis, Purification and Prop. of Hydrocarbons of Low Mol. Weight, Am. Pet. Inst. Res. Proj. 45, Eighth Annu. Rep., Ohio State Univ., June 30, 1946. [all data]
Henne and Greenlee, 1945
Henne, A.L.; Greenlee, K.W.,
Preparation and Physical Constants of Acetylenic Compounds,
J. Am. Chem. Soc., 1945, 67, 484-5. [all data]
Heisig and Davis, 1935
Heisig, G.B.; Davis, H.M.,
Physical Constants of Dimethylacetylene,
J. Am. Chem. Soc., 1935, 57, 339-40. [all data]
Yost, Osborne, et al., 1941, 2
Yost, D.M.; Osborne, D.W.; Garner, C.S.,
The Heat Capacity, Entropy, and Heats of Transition, Fusion, and Vaporization of Dimethylacetylene. Free Rotation in the Dimethylacetylene Molecule,
J. Am. Chem. Soc., 1941, 63, 3492. [all data]
Reid, 1972
Reid, Robert C.,
Handbook on vapor pressure and heats of vaporization of hydrocarbons and related compounds, R. C. Wilhort and B. J. Zwolinski, Texas A Research Foundation. College Station, Texas(1971). 329 pages.$10.00,
AIChE J., 1972, 18, 6, 1278-1278, https://doi.org/10.1002/aic.690180637
. [all data]
Osborne, Garner, et al., 1940
Osborne, D.W.; Garner, C.S.; Yost, D.M.,
The entropy of dimethylacetylene from low temperature calorimetric measurements. Free rotation in the dimethylacetylene molecule,
J. Chem. Phys., 1940, 8, 131. [all data]
Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw,
Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2
. [all data]
Yost, Osborne, et al., 1941, 3
Yost, D.M.; Osborne, D.W.; Garner, C.S.,
The heat capacity, entropy, and heats of transition, fusion, and vaporization of dimethylacetylene. Free rotation in the dimethylacetylene molecule,
J. Am. Chem. Soc., 1941, 63, 3492-34. [all data]
Stull, 1947
Stull, Daniel R.,
Vapor Pressure of Pure Substances. Organic and Inorganic Compounds,
Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022
. [all data]
Acree, 1991
Acree, William E.,
Thermodynamic properties of organic compounds: enthalpy of fusion and melting point temperature compilation,
Thermochimica Acta, 1991, 189, 1, 37-56, https://doi.org/10.1016/0040-6031(91)87098-H
. [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]
Bieri, Burger, et al., 1977
Bieri, G.; Burger, F.; Heilbronner, E.; Maier, J.P.,
Valence ionization enrgies of hydrocarbons,
Helv. Chim. Acta, 1977, 60, 2213. [all data]
Carlier, Dubois, et al., 1975
Carlier, P.; Dubois, J.E.; Masclet, P.; Mouvier, G.,
Spectres de photoelectrons des alcynes,
J. Electron Spectrosc. Relat. Phenom., 1975, 7, 55. [all data]
Ensslin, Bock, et al., 1974
Ensslin, W.; Bock, H.; Becker, G.,
Photoelectron spectra and molecular properties. XXX. π interactions in H3Si- H3C-substituted acetylenes,
J. Am. Chem. Soc., 1974, 96, 2757. [all data]
Brogli, Heilbronner, et al., 1973
Brogli, F.; Heilbronner, E.; Hornung, V.; Kloster-Jensen, E.,
230. Die photoelektronen-spektren methyl-substituierter Acetylene,
Helv. Chim. Acta, 1973, 56, 2171. [all data]
Lossing, 1972
Lossing, F.P.,
Free radicals by mass spectrometry. XLV. Ionization potentials and heats of formation of C3H3, C3H5, and C4H7 radicals and ions,
Can. J. Chem., 1972, 50, 3973. [all data]
Bieri and Asbrink, 1980
Bieri, G.; Asbrink, L.,
30.4-nm He(II) photoelectron spectra of organic molecules,
J. Electron Spectrosc. Relat. Phenom., 1980, 20, 149. [all data]
Coats and Anderson, 1957
Coats, F.H.; Anderson, R.C.,
Thermodynamic data from electron-impact measurements on acetylene and substituted acetylenes,
J. Am. Chem. Soc., 1957, 79, 1340. [all data]
Gal, Decouzon, et al., 2001
Gal, J.F.; Decouzon, M.; Maria, P.C.; Gonzalez, A.I.; Mo, O.; Yanez, M.; El Chaouch, S.; Guillemin, J.C.,
Acidity trends in alpha,beta-unsaturated alkanes, silanes, germanes, and stannanes,
J. Am. Chem. Soc., 2001, 123, 26, 6353-6359, https://doi.org/10.1021/ja004079j
. [all data]
Notes
Go To: Top, Condensed phase thermochemistry data, Phase change data, Gas phase ion energetics data, Mass spectrum (electron ionization), References
- Symbols used in this document:
AE Appearance energy Cp,liquid Constant pressure heat capacity of liquid IE (evaluated) Recommended ionization energy S°liquid Entropy of liquid at standard conditions Tboil Boiling point Tfus Fusion (melting) point Ttriple Triple point temperature ΔfusH Enthalpy of fusion ΔfusS Entropy of fusion ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions ΔsubH Enthalpy of sublimation ΔvapH Enthalpy of vaporization ΔvapH° Enthalpy of vaporization at standard conditions ΔvapS Entropy of vaporization - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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