Multicomponent Solubilities of Reactants and Products of Cyclohexane Oxidation in Supercritical Carbon Dioxide

Abstract

Cyclohexane oxidation starting with a homogeneous mixture in supercritical carbon dioxide (SC CO2) medium encounters phase separation as the products are formed. Multicomponent solubility data in the reacting system are therefore needed to ascertain whether it is due to condensation of the reactants, oxygen and cyclohexane, or the products, cyclohexanone, cyclohexanol, and water. In the present work, solubility measurements have been made for cyclohexanone and cyclohexanol in supercritical CO2 at 410, 423, and 433 K and in N2 at 423 K (N2 is taken as a homomorph for oxygen to avoid reaction). Solubility data have been measured in SC CO2 at 423 K for each of the three binary mixtures, (i) cyclohexane−cyclohexanone, (ii) cyclohexane−cyclohexanol, and (iii) cyclohexanone−cyclohexanol, at 170 and 205 bar. These data have been utilized to regress for each binary pair two adjustable parameters in the Peng−Robinson (P−R) EOS for predicting the multicomponent solubility data in a SC mixture of CO2 and O2 in the p...