Chemical data page
This page provides supplementary chemical data on isobutane .
Material Safety Data Sheet
The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS ) for this chemical from a reliable source such as SIRI , and follow its directions.
Structure and properties
Thermodynamic properties
Phase behavior
Triple point
113.55K (–159.6 °C), 0.019481 Pa
Critical point
407.7 K (134.6 °C), 3650 kPa
Std enthalpy change of fusion , Δfus H o
4.54 kJ/mol
Std entropy change of fusion , Δfus S o
39.92 J/(mol·K)
Std enthalpy change of vaporization , Δvap H o
21.3 kJ/mol
Std entropy change of vaporization , Δvap S o
81.46 J/(mol·K)
Solid properties
Std enthalpy change of formation , Δf H o solid
? kJ/mol
Standard molar entropy ,S o solid
? J/(mol K)
Heat capacity , cp
? J/(mol K)
Liquid properties
Std enthalpy change of formation , Δf H o liquid
? kJ/mol
Standard molar entropy ,S o liquid
200.79 J/(mol K)
Heat capacity , cp
129.70 J/(mol K) –253°C to –13°C
Gas properties
Std enthalpy change of formation , Δf H o gas
–134.2 kJ/mol
Standard molar entropy ,S o gas
249.7 J/(mol K)
Enthalpy of combustion , Δc H o
–2869 kJ/mol
Heat capacity , cp
95.21 J/(mol K) at 20°C
van der Waals' constants [ 1]
a = 1304.1 L2 kPa/mol2 b = 0.1142 liter per mole
Vapor pressure of liquid
P in mm Hg
1
10
40
100
400
760
1520
3800
7600
15200
30400
45600
T in °C
–109.2
–86.4
–68.4
–54.1
–27.1
–11.7
7.5
39.0
68.8
99.5
—
—
Table data obtained from CRC Handbook of Chemistry and Physics 44th ed.
Vapor pressure of iso -butane . From formula:
log
10
-->
P
m
m
H
g
=
6.74808
− − -->
882.80
240.0
+
T
{\displaystyle \scriptstyle \log _{10}P_{mmHg}=6.74808-{\frac {882.80}{240.0+T}}}
obtained from Lange's Handbook of Chemistry , 10th ed.
Spectral data
References
^ Lange's Handbook of Chemistry 10th ed, pp 1522-1524