Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Citronellal and methyl anthranilate (MA) are both nonpolar molecules with similar physical properties except for their molecular structures. The solubility of citronellal in supercritical carbon dioxide (SC-CO2) was measured using a static equilibrium system in the pressure range of (9.1 to 14.2) MPa and at (313.15 and 333.15) K. For MA, (9.1 to 24.3) MPa was used at the same temperatures. Solubility data of citronellal and MA in SC-CO2 were well correlated using the Chrastil equation and Peng Robinson equation of state. Under comparable operating conditions, the linear-chained citronellal solubility in SC-CO2 was three to four times higher than its aromatic derivative MA. The acentric factor of citronellal (? = 1.004) is higher than that of MA (? = 0.577), indicating that citronellal has larger molecular asymmetry. This difference allows less intermolecular binding energy but gives higher vapor pressure to citronellal, making it more readily soluble in SC-CO2. The results suggest that the acentric factor is a good indicator of molecular asymmetry of a solute and provides a preliminary estimate on solutes behavior in SC-CO2. Knowledge of the solubility behavior of such molecules in SC-CO2 is a prerequisite for designing efficient industry-scale systems for their extraction and fractionation.