1-Propanethiol Chemical Properties Melting point -113 °C Boiling point 67-68 °C(lit.) density 0.841 g/mL at 25 °C(lit.) vapor density 2.54 (vs air) vapor pressure 122 mm Hg ( 20 °C) refractive index n20/D 1.437(lit.) FEMA 3521 | PROPANETHIOL Fp −5 °F storage temp. Flammables area solubility 1.9g/l form Liquid pka pK1:10.86 (25°C) color Colorless