Dihydrolevoglucosenone (Cyrene), a Biobased Solvent for Liquid-Liquid Extraction Applications

Dihydrolevoglycosenone, commercially known as Cyrene, is a versatile biobased solvent reported for various applications including being a medium of chemical reactions and membrane manufacture. In this work, application of Cyrene in liquid-liquid extractions has been investigated. Four ternary systems have been assessed at 298.15 K, 323.15 K, and 348.15 K, keeping Cyrene and methylcyclohexane constant and changing the third compound to toluene, cyclohexanol, cyclohexanone, and cyclopentyl methyl ether. Studying these selected ternary systems yielded an indication of applicability of Cyrene in related industrial separation processes such as aromatic/aliphatic separations and in separations of oxygenates in the cyclohexane oxidation process. Key factors are biphasic system formation, distribution coefficients, and selectivity. All ternary systems showed type I liquid-liquid phase behavior with a selective extraction of ternary components from methylcyclohexane by Cyrene. The highest selectivity at 298.15 K was found for cyclohexanol with 61.4 +/- 4.33, followed by cyclohexanone with 44.1 +/- 8.63, while toluene and cyclopentyl methyl ether had a selectivity of, respectively, 12.0 +/- 0.89 and 6.4 +/- 0.08. Although Cyrene is applicable in all four ternary systems, the miscibility gap is narrow for the oxygenated species, indicating a limited operation window for liquid-liquid extraction which will be more severe at higher temperatures. Overall, the studies showed that there are certainly application windows for Cyrene. In the case of oxygenate extraction, a process with Cyrene appears energy-saving because the energy duty appears to be lower than when using water, the best alternative solvent, which is a low boiling solvent for this purpose.