Solubility of bioinsecticides in supercritical CO2. Experimental measurement and modeling with the GC-EOS.

Abstract

The knowledge of the solubility of natural compounds in supercritical CO2 (scCO2), as well as the development of suitable models for its description and/or prediction, is a key parameter in supercritical-based processes, as it determines the amount of fluid required or the highest concentration that can be obtained in the fluid phase in an impregnation, extraction, fractionation or particle formation system. In this work, the solubility of three natural volatile compounds with insecticidal activity (R-(+)-pulegone, thymoquinone and 1-octen-3-ol) is measured and modeled using the group contribution equation of state (GC-EOS). Goñi et al. have studied the scCO2-assisted impregnation of low density polyethylene films with thymoquinone and R-(+)-pulegone, for developing active packaging materials, showing the importance of the fluid phase concentration on impregnation yield and kinetics. Moreover, Sovová et al. have investigated the scCO2 extraction of thymoquinone from Monarda didyma and Monarda fistulosa. Fractionation with scCO2 has been proposed as an alternative methodology to reduce the content of pulegone in mint essential oils, as well as to recover bioactive compounds from dementholized mint oils. Therefore, the solubility of these compounds in scCO2 at typical process conditions is presented with the objective of providing useful data for the design and optimization of supercritical processes.