propanethiol

Propanethiol, or propan-1-thiol, is an aliphatic thiol with a three-carbon chain and a sulfhydryl group. The straight-chain isomer has the structure CH3CH2CH2-SH, while the secondary isomer, isopropanethiol (propan-2-thiol), has the structure CH3CH(SH)CH3. Both are colorless liquids at room temperature and are known for their strong, sulfurous odor, which is characteristic of mercaptans. They are flammable and have limited water solubility, but they dissolve in many organic solvents.

Chemical properties of propanethiols include the presence of the thiol (-SH) group, which behaves as a weak acid (thiols have higher acidity than alcohols) and can form disulfides upon oxidation (R-SH + R-SH → R-S-S-R + 2 H+ + 2 e−). The thiol group also participates in typical thiol chemistry, such as nucleophilic substitution and the formation of thioethers or thioesters under appropriate conditions.

Occurrences and uses of propanethiol include its role as an intermediate in the synthesis of sulfur-containing compounds. It is also used as an odorant in some natural gas formulations and, in trace amounts, as a flavor or fragrance component. In organic synthesis, propanethiol serves as a nucleophile and as a source of thiol groups for introducing sulfur functionality into molecules.

Safety and handling are important due to the strong odor and irritant properties of thiols. Propanethiol vapors can be irritating to the eyes, skin, and respiratory tract; it is also flammable. It should be used in well-ventilated areas with appropriate protective equipment and stored away from heat or sources of ignition.