Determinação do comportamento de fases a altas pressões dos sistemas CO2 + solvente orgânico + curcumina

Abstract

The Curcuma longa L. is a herbaceous perennial plant with medicinal properties, that belongs the family of Zingiberaceae. Such plant is cultivated in India, China and other countries with tropical climate. The rhizome is the part of the plant used in medical applications and it has a yellowish color and can be used as food colorants. Curcumin ((E,E)- 1,7-bis (4-hydroxy-3-methoxyphenyl) -1,6-heptadien-3,5-dione) is the principal non-volatile active compound of the rhizome. This curcuminoid has antioxidative, anti-carcinogenic, antimutagenic, anti-inflammatory and antifungal effects. The application of supercritical fluids as antisolvents for the precipitation of microparticles of curcumin can be an attractive technique due the low solubility of this substance in the supercritical fluid in comparison with the organic solvents used in conventional methods. The knowledge of the phase behavior of solute + solvent + antisolvent system is a crucial aspect for the development or optimization of production processes of microparticles. Thus, the objective of this work is to report phase equilibrium data for the system CO2 + ethanol + curcumin and CO2 + ethyl acetate + curcumin at high pressure and temperatures of 303, 313, 323 and 333 K. For this purpose a visual synthetic method in a equilibrium cell of variable-volume is used. For both systems were obtained data of Liquid-Vapor (LV) and Solid-Fluid (SF) transitions. The results obtained for the SF transitions show that CO2 as better antisolvent in the CO2 + ethyl acetate + curcumin system. In this case, the amount of CO2 used for the precipitation of curcumin is lower than the amount of CO2 employed in the CO2 + ethanol + curcumin system. The data of LV transition were predicted using the Peng-Robinson equation of state with only information from the binary systems CO2+ ethanol and CO2 + ethyl acetate. Experimental data of phase equilibrium constitute relevant information for the precipitation of curcumin using the supercritical antisolvent process.