Thermodynamics of mixtures of metal complexes with supercritical fluids

Abstract

This chapter deals with the thermodynamics of metal complexes in SCFs and primarily on solubility of metal complexes in scCO2. Such data are important in designing high pressure processes for scCO2 extraction of metals, for homogeneous catalytic reactions in scCO2 and synthesis of nanostructured materials in scCO2. Specifically, the solubility behavior of metal complexes in SCFs is discussed with an emphasis on the effect of chemical structure of various ligands on solubility. The possible reasons behind the enhancement of the solubility of the metal complexes in scCO2 due to the presence of fluorous groups in the ligands are provided. The static and dynamic experimental techniques used in the literature to measure the solubility of metal complexes in SCFs are reviewed. The equation of state (EOS) based methods to correlate and predict the solubility of metal complexes in SCFs are described and demonstrated for the prediction of solubility of Cu(acac)2 in scCO2 using the Peng Robinson EOS. The effects of entrainers on solubility are also discussed using the data in the literature. The good correlation between the solubility of the metal complexes and the solubility parameter of the ligand is presented.