As a refrigerant, isobutane poses a fire and explosion risk in addition to the hazards associated with non-flammable CFC refrigerants. Substitution of this refrigerant for motor vehicle air conditioning systems not originally designed for isobutane is widely prohibited or discouraged. R600a (isobutane) is refrigerant grade isobutane used as a replacement for R12 and R134a in a variety of high-temperature refrigeration applications.

R600a (isobutane) is a hydrocarbon that is becoming increasingly popular due to its low Global Warming Potential (GWP). It is the refrigerant of choice for domestic and light commercial refrigeration units, including fridges and freezers, drink dispensers and standalone display units.
 

Properties
Chemical formula	C4H10
Molar mass	58.124 g·mol−1
Appearance	Colorless gas
Odor	Odorless
Density	2.51 kg/m3 (at 15 °C, 100 kPa) 563 kg/m3 (at 15 °C, boiling liquid)
Melting point	−159.42 °C (−254.96 °F; 113.73 K)[4]
Boiling point	−11.7 °C (10.9 °F; 261.4 K)[4]
Solubility in water	48.9 mg⋅L−1 (at 25 °C (77 °F))[2]
Vapor pressure	3.1 atm (310 kPa) (at 21 °C (294 K; 70 °F))[3]
Henry's law constant (kH)	8.6 nmol⋅Pa−1⋅kg−1
Conjugate acid	Isobutanium
Magnetic susceptibility (χ)	−51.7·10−6 cm3/mol
Thermochemistry
Heat capacity (C)	96.65 J⋅K−1⋅mol−1
Std enthalpy of formation (ΔfH⦵298)	−134.8 – −133.6 kJ⋅mol−1
Std enthalpy of combustion (ΔcH⦵298)	−2.86959 – −2.86841 MJ⋅mol−1
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H220
Precautionary statements	P210
NFPA 704 (fire diamond)
Flash point	−83 °C (−117 °F; 190 K)
Autoignition temperature	460 °C (860 °F; 733 K)
Explosive limits	1.4–8.3%
NIOSH (US health exposure limits):
PEL (Permissible)	None[5]
REL (Recommended)	TWA 800 ppm (1900 mg/m3)[5]
IDLH (Immediate danger)	N.D.[5]