Physical Property Molecular Formular (CH3)CHCH3 Component Isobutane Molecular Weight 58.12 Boiling Point℃ -11.70 Critical Temperature℃ 134.71 Critical Pressure Mpa 3.64 GWP 3 ODP 0 Quality Index Purity ≧99.9％ Moisture PPM ≦10 Acidity PPM ≦1 Vapor Residue PPM ≦100 Appearance Colorless,No turbid Odor No strange stench