Butane, 2-methyl-
- Formula: C5H12
- Molecular weight: 72.1488
- IUPAC Standard InChIKey: QWTDNUCVQCZILF-UHFFFAOYSA-N
- CAS Registry Number: 78-78-4
- 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: iso-Pentane; 1,1,2-Trimethylethane; 2-Methylbutane; iso-C5H12; Ethyldimethylmethane; Isoamylhydride; Exxsol isopentane S; 1,1-Dimethylpropane; Methylbutane; NSC 119476
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Condensed phase thermochemistry data
Go To: Top, Phase change data, Reaction thermochemistry 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 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 |
---|---|---|---|---|---|
ΔfH°liquid | -42.58 ± 0.21 | kcal/mol | Ccb | Good, 1970 | Reanalyzed by Pedley, Naylor, et al., 1986, Original value = -42.76 ± 0.14 kcal/mol; ALS |
ΔfH°liquid | -42.86 ± 0.20 | kcal/mol | Ccb | Prosen and Rossini, 1945 | ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°liquid | -837.57 ± 0.20 | kcal/mol | Ccb | Good, 1970 | Reanalyzed by Pedley, Naylor, et al., 1986, Original value = -837.39 ± 0.11 kcal/mol; Corresponding ΔfHºliquid = -42.58 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS |
ΔcH°liquid | -837.30 ± 0.18 | kcal/mol | Ccb | Prosen and Rossini, 1945 | Corresponding ΔfHºliquid = -42.85 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°liquid | 62.239 | cal/mol*K | N/A | Guthrie and Huffman, 1943 | DH |
S°liquid | 62.390 | cal/mol*K | N/A | Schumann, Aston, et al., 1942 | DH |
S°liquid | 60.80 | cal/mol*K | N/A | Parks, Huffman, et al., 1930 | Extrapolation below 90 K, 57.49 J/mol*K.; DH |
Constant pressure heat capacity of liquid
Cp,liquid (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
39.32 | 298.3 | Czarnota, 1988 | T = 289 to 299 K. p = 0.1 MPa. Unsmoothed experimental datum. Cp values provided over the pressure range 0.1 to 820 MPa.; DH |
39.400 | 298.15 | Guthrie and Huffman, 1943 | T = 13 to 300 K.; DH |
40.490 | 290. | Schumann, Aston, et al., 1942 | T = 20 to 290 K.; DH |
37.60 | 275.8 | Parks, Huffman, et al., 1930 | T = 80 to 276 K. Value is unsmoothed experimental datum.; DH |
Phase change data
Go To: Top, Condensed phase thermochemistry data, Reaction thermochemistry 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 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
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing
CAL - James S. Chickos, William E. Acree, Jr., Joel F. Liebman, Students of Chem 202 (Introduction to the Literature of Chemistry), University of Missouri -- St. Louis
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Tboil | 301.1 ± 0.2 | K | AVG | N/A | Average of 67 out of 76 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 113. ± 1. | K | AVG | N/A | Average of 10 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 113.37 | K | N/A | Guthrie and Huffman, 1943, 2 | Uncertainty assigned by TRC = 0.02 K; TRC |
Ttriple | 113.39 | K | N/A | Schumann, Aston, et al., 1942, 2 | Uncertainty assigned by TRC = 0.05 K; TRC |
Ttriple | 112.6 | K | N/A | Parks, Huffman, et al., 1930, 2 | Uncertainty assigned by TRC = 0.3 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Tc | 461. ± 5. | K | AVG | N/A | Average of 9 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Pc | 33.4 ± 0.5 | atm | N/A | Daubert, 1996 | |
Pc | 33.37 | atm | N/A | Das, Reed, et al., 1977 | Uncertainty assigned by TRC = 0.5000 atm; TRC |
Pc | 33.660 | atm | N/A | Vohra and Kobe, 1959 | Uncertainty assigned by TRC = 0.09998 atm; TRC |
Pc | 32.919 | atm | N/A | Young, 1910 | Uncertainty assigned by TRC = 0.658 atm; TRC |
Pc | 32.27 | atm | N/A | Altschul, 1893 | Uncertainty assigned by TRC = 0.9679 atm; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Vc | 0.306 | l/mol | N/A | Daubert, 1996 | |
Quantity | Value | Units | Method | Reference | Comment |
ρc | 3.27 ± 0.05 | mol/l | N/A | Daubert, 1996 | |
ρc | 3.247 | mol/l | N/A | Holcomb, Magee, et al., 1995 | Uncertainty assigned by TRC = 0.06 mol/l; TRC |
ρc | 3.27 | mol/l | N/A | Das, Reed, et al., 1977 | Uncertainty assigned by TRC = 0.03 mol/l; TRC |
ρc | 3.27 | mol/l | N/A | Vohra and Kobe, 1959 | Uncertainty assigned by TRC = 0.1 mol/l; TRC |
ρc | 3.247 | mol/l | N/A | Young, 1910 | Uncertainty assigned by TRC = 0.06 mol/l; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ΔvapH° | 6.028 | kcal/mol | N/A | Majer and Svoboda, 1985 | |
ΔvapH° | 5.93 | kcal/mol | N/A | Reid, 1972 | AC |
ΔvapH° | 5.94 ± 0.03 | kcal/mol | V | Scott, McCullough, et al., 1951 | flow calorimeter and metal cycling vaporizer; ALS |
ΔvapH° | 5.98 | kcal/mol | C | Schumann, Aston, et al., 1942 | AC |
Enthalpy of vaporization
ΔvapH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
5.901 | 301. | N/A | Majer and Svoboda, 1985 | |
5.9350 | 293.95 | N/A | Schumann, Aston, et al., 1942 | P = 79.15 kPa; DH |
6.43 | 270. | N/A | Ewing and Goodwin, 1991 | Based on data from 255. to 323. K.; AC |
6.81 | 231. | A | Stephenson and Malanowski, 1987 | Based on data from 216. to 323. K.; AC |
6.02 | 315. | A | Stephenson and Malanowski, 1987 | Based on data from 300. to 460. K.; AC |
6.02 | 335. | A | Stephenson and Malanowski, 1987 | Based on data from 320. to 391. K.; AC |
5.93 | 400. | A | Stephenson and Malanowski, 1987 | Based on data from 385. to 416. K.; AC |
6.05 | 427. | A | Stephenson and Malanowski, 1987 | Based on data from 412. to 460. K.; AC |
5.83 | 310. | N/A | Das, Reed, et al., 1977, 2 | AC |
5.14 | 350. | N/A | Das, Reed, et al., 1977, 2 | AC |
4.30 | 390. | N/A | Das, Reed, et al., 1977, 2 | AC |
3.08 | 430. | N/A | Das, Reed, et al., 1977, 2 | AC |
7.22 | 205. | N/A | Stull, 1947 | Based on data from 190. to 300. K.; AC |
6.26 | 295. | MM | Willingham, Taylor, et al., 1945 | Based on data from 289. to 301. K.; AC |
Enthalpy of vaporization
ΔvapH =
A exp(-βTr) (1 − Tr)β
ΔvapH =
Enthalpy of vaporization (at saturation pressure)
(kcal/mol)
Tr = reduced temperature (T / Tc)
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Temperature (K) | A (kcal/mol) | β | Tc (K) | Reference | Comment |
---|---|---|---|---|---|
279. to 301. | 9.326 | 0.267 | 460.4 | Majer and Svoboda, 1985 |
Entropy of vaporization
ΔvapS (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
20.19 | 293.95 | Schumann, Aston, et al., 1942 | P; DH |
Antoine Equation Parameters
log10(P) = A − (B / (T + C))
P = vapor pressure (atm)
T = temperature (K)
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Temperature (K) | A | B | C | Reference | Comment |
---|---|---|---|---|---|
190.3 to 300.9 | 3.90364 | 1018.516 | -40.081 | Stull, 1947 | Coefficents calculated by NIST from author's data. |
300.9 to 453.5 | 3.96612 | 1021.864 | -43.231 | Stull, 1947 | Coefficents calculated by NIST from author's data. |
289.44 to 301.74 | 3.90886 | 1020.012 | -40.053 | Williamham, Taylor, et al., 1945 |
Enthalpy of fusion
ΔfusH (kcal/mol) | Temperature (K) | Reference | Comment |
---|---|---|---|
1.2322 | 113.37 | Guthrie and Huffman, 1943 | DH |
1.226 | 113.39 | Schumann, Aston, et al., 1942 | DH |
1.23 | 113.4 | Domalski and Hearing, 1996 | AC |
1.222 | 112.6 | Parks, Huffman, et al., 1930 | DH |
Entropy of fusion
ΔfusS (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
10.87 | 113.37 | Guthrie and Huffman, 1943 | DH |
10.81 | 113.39 | Schumann, Aston, et al., 1942 | DH |
10.81 | 113.4 | Domalski and Hearing, 1996 | CAL |
10.85 | 112.6 | Parks, Huffman, et al., 1930 | DH |
Reaction thermochemistry data
Go To: Top, Condensed phase thermochemistry data, Phase change 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: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.
Individual Reactions
By formula: H2 + C5H10 = C5H12
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -30.341 | kcal/mol | Chyd | Dolliver, Gresham, et al., 1937 | gas phase; At 355 °K |
ΔrH° | -28.25 ± 0.10 | kcal/mol | Chyd | Kistiakowsky, Ruhoff, et al., 1936 | gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -28.49 ± 0.36 kcal/mol; At 355 K |
By formula: H2 + C5H10 = C5H12
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -30.19 ± 0.06 | kcal/mol | Chyd | Dolliver, Gresham, et al., 1937 | gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -30.34 ± 0.06 kcal/mol; At 355 °K |
By formula: C5H12 = C5H12
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -1.861 | kcal/mol | Eqk | Pines, Kvetinskas, et al., 1945 | gas phase; Heat of isomerization |
By formula: H2 + C5H10 = C5H12
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -26.68 ± 0.06 | kcal/mol | Chyd | Kistiakowsky, Ruhoff, et al., 1936 | gas phase |
References
Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Good, 1970
Good, W.D.,
The enthalpies of combustion and formation of the isomeric pentanes,
J. Chem. Thermodyn., 1970, 2, 237-244. [all data]
Pedley, Naylor, et al., 1986
Pedley, J.B.; Naylor, R.D.; Kirby, S.P.,
Thermochemical Data of Organic Compounds, Chapman and Hall, New York, 1986, 1-792. [all data]
Prosen and Rossini, 1945
Prosen, E.J.; Rossini, F.D.,
Heats of combustion and formation of the paraffin hydrocarbons at 25° C,
J. Res. NBS, 1945, 263-267. [all data]
Guthrie and Huffman, 1943
Guthrie, G.B., Jr.; Huffman, H.M.,
Thermal data. XVI. The heat capacity and entropy of isopentane. The absence of a reported anomaly,
J. Am. Chem. Soc., 1943, 65, 1139-1143. [all data]
Schumann, Aston, et al., 1942
Schumann, S.C.; Aston, J.G.; Sagenkahn, M.,
The heat capacity and entropy, heats of fusion and vaporization and the vapor pressures of isopentane,
J. Am. Chem. Soc., 1942, 64, 1039-1043. [all data]
Parks, Huffman, et al., 1930
Parks, G.S.; Huffman, H.M.; Thomas, S.B.,
Thermal data on organic compounds. VI. The heat capacities, entropies and free energies of some saturated, non-benzenoid hydrocarbons,
J. Am. Chem. Soc., 1930, 52, 1032-1041. [all data]
Czarnota, 1988
Czarnota, I.,
Heat capacity of 2-methylbutane at high pressures,
J. Chem. Thermodynam., 1988, 20, 457-462. [all data]
Guthrie and Huffman, 1943, 2
Guthrie, G.B.; Huffman, H.M.,
Thermal data. XVI. the heat capacity and entropy of isopentane. the absence of a reported anomaly.,
J. Am. Chem. Soc., 1943, 65, 1139. [all data]
Schumann, Aston, et al., 1942, 2
Schumann, S.C.; Aston, J.G.; Sagenkahn, M.,
The Heat Capacity and Entropy, Heats of Fusion and Vaporization and the Vapor Pressures of Isopentane,
J. Am. Chem. Soc., 1942, 64, 1039. [all data]
Parks, Huffman, et al., 1930, 2
Parks, G.S.; Huffman, H.M.; Thomas, S.B.,
Thermal Data on Organic Compounds VI. The Heat Capacities, Entropies and Free Energies of Some Saturated, Non-Benzenoid Hydrocarbons,
J. Am. Chem. Soc., 1930, 52, 1032-41. [all data]
Daubert, 1996
Daubert, T.E.,
Vapor-Liquid Critical Properties of Elements and Compounds. 5. Branched Alkanes and Cycloalkanes,
J. Chem. Eng. Data, 1996, 41, 365-372. [all data]
Das, Reed, et al., 1977
Das, T.R.; Reed, C.O.; Eubank, P.T.,
PVT Surface and Thermodindynamic Properties of Isopentane.,
J. Chem. Eng. Data, 1977, 22, 9. [all data]
Vohra and Kobe, 1959
Vohra, S.P.; Kobe, K.A.,
Volumetric Behaviour and Critical Constants of Isopentane,
J. Chem. Eng. Data, 1959, 4, 329. [all data]
Young, 1910
Young, S.,
The Internal Heat of Vaporization constants of thirty pure substances,
Sci. Proc. R. Dublin Soc., 1910, 12, 374. [all data]
Altschul, 1893
Altschul, M.,
The critical values of some organic compounds,
Z. Phys. Chem., Stoechiom. Verwandtschaftsl., 1893, 11, 577. [all data]
Holcomb, Magee, et al., 1995
Holcomb, C.D.; Magee, J.W.; Haynes, W.M.,
Density Measurements on Natural Gas Liquids, Research Report RR-147, Gas Processors Association Project 916, 1995. [all data]
Majer and Svoboda, 1985
Majer, V.; Svoboda, V.,
Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation, Blackwell Scientific Publications, Oxford, 1985, 300. [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]
Scott, McCullough, et al., 1951
Scott, D.W.; McCullough, J.P.; Williamson, K.D.; Waddington, G.,
Rotational isomerism and thermodynamic functions of 2-methylbutane and 2,3-dimethylbutane. Vapor heat capacity and heat of vaporization of 2-methylbutane,
J. Am. Chem. Soc., 1951, 73, 1707-17. [all data]
Ewing and Goodwin, 1991
Ewing, M.B.; Goodwin, A.R.H.,
Vapour pressures of 2-methylbutane determined using comparative ebulliometry,
The Journal of Chemical Thermodynamics, 1991, 23, 12, 1163-1168, https://doi.org/10.1016/S0021-9614(05)80149-1
. [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]
Das, Reed, et al., 1977, 2
Das, Tarun R.; Reed, Charles O.; Eubank, Philip T.,
PVT surface and thermodynamic properties of neopentane,
J. Chem. Eng. Data, 1977, 22, 1, 16-21, https://doi.org/10.1021/je60072a025
. [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]
Willingham, Taylor, et al., 1945
Willingham, C.B.; Taylor, W.J.; Pignocco, J.M.; Rossini, F.D.,
Vapor pressures and boiling points of some paraffin, alkylcyclopentane, alkylcyclohexane, and alkylbenzene hydrocarbons,
J. RES. NATL. BUR. STAN., 1945, 35, 3, 219-17, https://doi.org/10.6028/jres.035.009
. [all data]
Williamham, Taylor, et al., 1945
Williamham, C.B.; Taylor, W.J.; Pignocco, J.M.; Rossini, F.D.,
Vapor Pressures and Boiling Points of Some Paraffin, Alkylcyclopentane, Alkylcyclohexane, and Alkylbenzene Hydrocarbons,
J. Res. Natl. Bur. Stand. (U.S.), 1945, 35, 3, 219-244, https://doi.org/10.6028/jres.035.009
. [all data]
Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D.,
Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III,
J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985
. [all data]
Dolliver, Gresham, et al., 1937
Dolliver, M.a.; Gresham, T.L.; Kistiakowsky, G.B.; Vaughan, W.E.,
Heats of organic reactions. V. Heats of hydrogenation of various hydrocarbons,
J. Am. Chem. Soc., 1937, 59, 831-841. [all data]
Kistiakowsky, Ruhoff, et al., 1936
Kistiakowsky, G.B.; Ruhoff, J.R.; Smith, H.A.; Vaughan, W.E.,
Heats of organic reactions. III. Hydrogenation of some higher olefins,
J. Am. Chem. Soc., 1936, 58, 137-145. [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]
Pines, Kvetinskas, et al., 1945
Pines, H.; Kvetinskas, B.; Kassel, L.S.; Ipatieff, V.N.,
Determination of equilibrium constants for butanes and pentanes,
J. Am. Chem. Soc., 1945, 67, 631-637. [all data]
Notes
Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, References
- Symbols used in this document:
Cp,liquid Constant pressure heat capacity of liquid Pc Critical pressure S°liquid Entropy of liquid at standard conditions Tboil Boiling point Tc Critical temperature Tfus Fusion (melting) point Ttriple Triple point temperature Vc Critical volume ΔcH°liquid Enthalpy of combustion of liquid at standard conditions ΔfH°liquid Enthalpy of formation of liquid at standard conditions ΔfusH Enthalpy of fusion ΔfusS Entropy of fusion ΔrH° Enthalpy of reaction at standard conditions ΔvapH Enthalpy of vaporization ΔvapH° Enthalpy of vaporization at standard conditions ΔvapS Entropy of vaporization ρc Critical density - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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