Solubilities of Palmitic Acid + Capsaicin in Supercritical Carbon Dioxide

Solubilities of a solid binary mixture of palmitic acid and capsaicin in supercritical carbon dioxide (CO₂) are reported in this work. Measurements were carried out in a semiflow apparatus at 308.15 and 328.15 K, and pressures ranging from 10 to 35 MPa. Experiments were replicated at least three times in order to check for the repeatability. The suitability of this apparatus was verified by determining the solubility of naphthalene and of an equimolar solid binary mixture constituted by naphthalene and phenanthrene in supercritical CO₂. Solubilities of naphthalene are available in the literature and our measurements were found to be in good agreement with those vast data sets. Additionally, the method proposed by Mendez-Santiago and Teja to test the self-consistency of experimental data was used. Regarding the solid mixture naphthalene + phenanthrene, our results also agree with some literature data. The palmitic acid + capsaicin mixture was also prepared equimolarly. Solubility of palmitic acid was higher than that of capsaicin in the supercritical solvent. Besides, solubility of capsaicin and palmitic acid in the ternary system (solute + solute + CO₂) was not significantly improved compared with those reported elsewhere for the binary systems (solute + CO₂).