Solubility of androstenedione in lower alcohols

• Solubility of androstenedione in lower alcohols was investigated.
• Solubility predictions by COSMO-RS agreed with experimental data well.
• The thermodynamic functions of solution and mixture were calculated.
• Solute–solvent interactions were evaluated based on COSMO-RS computation.

Androstenedione (AD) solubilities in methanol, ethanol, 2-propanol, and 1-butanol were measured from 277.65 K to 319.45 K with medium-throughput experiments. The results show that AD solubilities increase with increasing temperature and solvent polarity. The experimental data are well correlated by modified Apelblat, λhλh, Margules, Wilson, NRTL, and UNIQUAC models, and the NRTL model obtains the best fitting results. The thermodynamic functions (i.e., Gibbs free energy, enthalpy, and entropy of solution and mixture) are calculated using the van’t Hoff and NRTL equations. Molecular interaction energies between AD and alcohols are calculated by COSMO-RS to investigate the effects of temperature and solvent polarity on AD solubility, and predicted AD solubilities in different alcohols agree well with the experimental data. The results suggest that temperature influence on AD solubility is driven by cavity formation enthalpy, whereas hydrogen bonding and electrostatic interactions between AD and alcohol molecules play a key role in solvent polarity effect on AD solubility.

σ-Profiles and COSMO-cavities of studied compounds. The blue color indicates a negative surface screening charge resulting from positive partial charges within the molecule. The red color indicates a positive surface charge and green symbolizes almost neutral charges.Figure optionsDownload as PowerPoint slide