Abstract

Experimental solubility data (pressure-concentration) of capsaicin in high-pressure carbon dioxide at three temperatures has been tested for consistency and then used to determine the sublimation pressure of capsaicin. The experimental data have been modeled and thermodynamically tested using the Peng-Robinson equation of state with the mixing rules of Wong and Sandler using a method previously developed by one of the authors. The system capsaicin + carbon dioxide is highly asymmetric and presents inherent difficulties of analysis. Despite this, the model employed in this work allows for the correlation of the solubility of solid capsaicin in the high-pressure gas phase with deviations much lower than other models presented in the literature for asymmetric mixtures. Therefore, the sublimation pressure determined by the proposed method can be used with confidence in modeling and simulation processes where the sublimation pressure of capsaicin is required. © 2006 American Chemical Society.