Abstract

Terpene-based eutectic mixtures were evaluated as green physical solvents for CO2 capture through an integrated multiscale framework. COSMO-RS screening of 40 terpenes identified camphor as a suitable base component and selected four binary mixtures (2:3 mol ratio) with thymol, menthol, carvone, and eucalyptol. Density and dynamic viscosity were measured from 293.15 to 333.15 K at atmospheric pressure, and CO2 solubility from 303.15 to 323.15 K at pressures up to 20 bar. Results were modeled with PC-SAFT and molecular dynamics simulations including alchemical free energy calculations. Camphor-carvone and camphor-eucalyptol exhibited Henry's law constants of 85-105 bar, significantly lower than the hydroxyl-containing systems (106-143 bar). Spatial distribution functions showed that hydrogen-bond donors competed with CO2 for the camphor carbonyl coordination site, whereas carvone and eucalyptol preserved it and added oxygen-based coordination points. Solvent-solvent hydrogen bonding emerged as a governing design variable for CO2 affinity in terpene-derived mixtures.