Home Symbol which looks like a small house Up Solid circle with an upward pointer in it

Isobutane

Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.


Gas phase thermochemistry data

Go To: Top, Condensed phase 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
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity Value Units Method Reference Comment
Deltafgas-32.07 ± 0.15kcal/molCcbPittam and Pilcher, 1972ALS
Deltafgas-32.42 ± 0.13kcal/molCmProsen, Maron, et al., 1951see Prosen and Rossini, 1945, Rossini, 1935; ALS
Quantity Value Units Method Reference Comment
Deltacgas-685.71 ± 0.14kcal/molCcbPittam and Pilcher, 1972Corresponding «DELTA»fgas = -32.07 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Deltacgas-685.37 ± 0.11kcal/molCmProsen, Maron, et al., 1951see Prosen and Rossini, 1945, Rossini, 1935; Corresponding «DELTA»fgas = -32.41 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS

Constant pressure heat capacity of gas

Cp,gas (cal/mol*K) Temperature (K) Reference Comment
8.32050.Chen S.S., 1975Recommended values are in good agreement with those calculated by [ Pitzer K.S., 1946].; GT
11.30100.
14.41150.
17.17200.
21.49273.15
23.10298.15
23.22300.
29.739400.
35.669500.
40.719600.
45.000700.
48.671800.
51.850900.
54.6011000.
57.0001100.
59.0701200.
60.8801300.
62.4501400.
63.8191500.

Constant pressure heat capacity of gas

Cp,gas (cal/mol*K) Temperature (K) Reference Comment
19.67 ± 0.01243.15Ernst G., 1970Other experimental values of heat capacity [ Sage B.H., 1937, Sage B.H., 1938] are less accurate, see [ Chen S.S., 1975]. Please also see Dailey B.P., 1943, Wacker P.F., 1947.; GT
21.50 ± 0.01273.15
22.76 ± 0.024293.15
24.061 ± 0.024313.15
25.423 ± 0.026333.15
26.209347.6
26.707 ± 0.026353.15
26.900359.4
28.590387.5
32.751452.5
36.551520.9
38.549561.7
40.559605.3
44.259692.7

Condensed phase thermochemistry data

Go To: Top, Gas phase 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 by: Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
liquid47.990cal/mol*KN/AAston, Kennedy, et al., 1940 
liquid47.49cal/mol*KN/AParks, Shomate, et al., 1937Extrapolation below 67 K, 44.02 J/mol*K.

Constant pressure heat capacity of liquid

Cp,liquid (cal/mol*K) Temperature (K) Reference Comment
30.999260.Aston, Kennedy, et al., 1940T = 20 to 260 K.
30.69258.3Parks, Shomate, et al., 1937T = 79 to 261 K. Value is unsmoothed experimental datum.

References

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

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Pittam and Pilcher, 1972
Pittam, D.A.; Pilcher, G., Measurements of heats of combustion by flame calorimetry. Part 8.-Methane, ethane, propane, n-butane and 2-methylpropane, J. Chem. Soc. Faraday Trans. 1, 1972, 68, 2224-2229. [all data]

Prosen, Maron, et al., 1951
Prosen, E.J.; Maron, F.W.; Rossini, F.D., Heats of combustion, formation, and insomerization of ten C4 hydrocarbons, J. Res. NBS, 1951, 46, 106-112. [all data]

Prosen and Rossini, 1945
Prosen, E.J.; Rossini, F.D., Heats of formation and combustion of 1,3-butadiene and styrene, J. Res. NBS, 1945, 34, 59-63. [all data]

Rossini, 1935
Rossini, F.D., Heat of combustion of isobutane, J. Res. NBS, 1935, 15, 357-361. [all data]

Chen S.S., 1975
Chen S.S., Ideal gas thermodynamic properties and isomerization of n-butane and isobutane, J. Phys. Chem. Ref. Data, 1975, 4, 859-869. [all data]

Pitzer K.S., 1946
Pitzer K.S., The entropies and related properties of branched paraffin hydrocarbons, Chem. Rev., 1946, 39, 435-447. [all data]

Ernst G., 1970
Ernst G., Ideal and real gas state heat capacities Cp of C3H8, i-C4H10, C2F5Cl, CH2ClCF3, CF2ClCFCl2, and CHF2Cl, J. Chem. Thermodyn., 1970, 2, 787-791. [all data]

Sage B.H., 1937
Sage B.H., Phase equilibria in hydrocarbon systems. XX. Isobaric heat capacity of gaseous propane, n-butane, isobutane, and n-pentane, Ind. Eng. Chem., 1937, 29, 1309-1314. [all data]

Sage B.H., 1938
Sage B.H., Phase equilibrium in hydrocarbon systems. Thermodynamic properties of isobutane, Ind. Eng. Chem., 1938, 30, 673-681. [all data]

Dailey B.P., 1943
Dailey B.P., Heat capacities and hindered rotation in n-butane and isobutane, J. Am. Chem. Soc., 1943, 65, 44-46. [all data]

Wacker P.F., 1947
Wacker P.F., Heat capacities of gaseous oxygen, isobutane, and 1-butene from -30 to +90 C, J. Res. Nat. Bur. Stand., 1947, 38, 651-659. [all data]

Aston, Kennedy, et al., 1940
Aston, J.G.; Kennedy, R.M.; Schumann, S.C., The heat capacity and entropy, heats of fusion and vaporization and the vapor pressure of isobutane, J. Am. Chem. Soc., 1940, 62, 2059-2063. [all data]

Parks, Shomate, et al., 1937
Parks, G.S.; Shomate, C.H.; Kennedy, W.D.; Crawford, B.L., Jr., The entropies of n-butane and isobutane, with some heat capacity data for isobutane, J. Chem. Phys., 1937, 5, 359-363. [all data]


Notes

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