Chemistry:Isobutane (data page)

Short description: 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

Structure and properties
Index of refraction, nD	?
Abbe number	?
Dielectric constant, εr	? ε0 at ? °C
Bond strength	?
Bond length	?
Bond angle	?
Magnetic susceptibility	?
Surface tension	10.3 dyn/cm at 20°C     P 300 kPa

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, ΔfusHo	4.54 kJ/mol
Std entropy change of fusion, ΔfusSo	39.92 J/(mol·K)
Std enthalpy change of vaporization, ΔvapHo	21.3 kJ/mol
Std entropy change of vaporization, ΔvapSo	81.46 J/(mol·K)
Solid properties
Std enthalpy change of formation, ΔfHosolid	? kJ/mol
Standard molar entropy, Sosolid	? J/(mol K)
Heat capacity, cp	? J/(mol K)
Liquid properties
Std enthalpy change of formation, ΔfHoliquid	? kJ/mol
Standard molar entropy, Soliquid	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, ΔfHogas	–134.2 kJ/mol
Standard molar entropy, Sogas	249.7 J/(mol K)
Enthalpy of combustion, ΔcHo	–2869 kJ/mol
Heat capacity, cp	95.21 J/(mol K) at 20°C
van der Waals' constants	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: [math]\displaystyle{ \scriptstyle \log_{10} P_{mmHg} = 6.74808 - \frac {882.80} {240.0+T} }[/math] obtained from Lange's Handbook of Chemistry, 10th ed.

Spectral data

UV-Vis
λmax	? nm
Extinction coefficient, ε	?
IR
Major absorption bands	? cm−1
NMR
Proton NMR
Carbon-13 NMR
Other NMR data
MS
Masses of main fragments