Solubility measurement of a pigment (Phthalocyanine green) in supercritical carbon dioxide: Experimental correlations and thermodynamic modeling

Abstract

Solubility of solid components in supercritical carbon dioxide (SC-CO2) is very important for the design of chemical processes and development of supercritical applications. Correlations and predictive methods are currently being extended to generate solubility data. In this work, for the first time, solubility of Phthalocyanine green (Pc-G) in SC-CO2 was determined at pressures and temperatures ranging within 100–350 bar and 308.15–338.15 K, respectively. The mole fractions of Phthalocyanine green dissolved in SC-CO2 were obtained in the range of 0.01 × 10−5 to 12.12 × 10−5. The solubility data of Pc-G was correlated using equations of state (EoSs), density-based models, and modified Wilson's model. The considered EoSs included Soave–Redlich–Kwong (SRK), Peng–Robinson (PR), quadrupolar cubic plus association theory (qCPA EoS), and the Perturbed-Chain Polar Statistical Associating Fluid Theory (PCP-SAFT EoS). Moreover, the density-based (semi-empirical) models proposed by Chrastil, Bartle et al., Bian et al., and Khansary et al., were considered in this study. Statistical criteria (AARD, Radj, F-value) were investigated to evaluate accuracy of the models. Results of the analysis of variance (ANOVA) demonstrated the superiority of SRK and PR models over other models for estimating the solubility of Pc-G in SC-CO2.