C3H8O2 Isomers: Insights into Potential Interstellar Species

2-Methoxyethanol, with a formula C₃H₈O₂, was recently identified in the massive protocluster NGC 6334I.

However, its structural isomers, 1,2-propanediol and 1,3-propanediol, remain undetected despite extensive searches in the Sgr B2 region. In this study, we explored the potential energy surface of the C₃H₈O₂ system using CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ calculations, identifying 11 species, with the geminal diols 2,2-propanediol and 1,1-propanediol as the most stable forms.

We examined the gas-phase decomposition barrier of these geminal diols and found that 1,1-propanediol is thermodynamically stable at low temperatures (10–150 K).

C₃H₈O₂ isomers with energies below 30 kcal/mol are relevant to the ISM, as they have been identified or tentatively detected in irradiation experiments of ice analogs of CO, H₂O, and CH₃OH.

C3H8O2 Isomers: Insights into Potential Interstellar Species, J Phys Chem A. via PubMed (open access)

Astrobiology, Astrochemistry,