Bubble-point measurements for the system CO2 + aqueous ethanol solutions of boldo leaf antioxidant components (boldine and catechin) at high pressures |
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Authors: | Juan C de la Fuente Gonzalo Núñez José M del Valle |
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Institution: | 1. Departamento de Procesos Químicos, Biotecnológicos y Ambientales, Universidad Técnica Federico Santa María, Avda. España 1680, Valparaiso, Chile;2. Departamento de Ingeniería Química y Bioprocesos, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna 4860, Macul, Santiago, Chile |
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Abstract: | The bubble-points pressures of solute(s) + ethanol + water + CO2 mixtures were determined visually using a synthetic method in an experimental apparatus that included a variable-volume equilibrium cell. Tested solutes included boldo leaf tincture, a boldine + catechin mixture, pure boldine, and pure catechin. Uncertainties in bubble-point pressures were estimated to be <5%, based on comparisons with literature values and replicate measurements. The largest effect we observed was an average increase of 205% in the bubble-point pressure when decreasing the ethanol-to-water ratio from 63:37 to 37:63 (w/w). The bubble-point pressure increased 11% when increasing the temperature from 313 to 343 K, and decreased 8.2% when increasing the concentration of solids from 400 to 1500 ppm. The bubble-point pressure was higher for boldo leaf tincture than for a boldine + catechin mixture having the same boldine-to-catechin weight ratio, but this was partially due to a lower content of solids in the tincture. On the other hand, bubble-point pressures of the boldine + catechin mixture were marginally (0.33%) higher than the weighed average of the bubble-point pressures for pure boldine and pure catechin. |
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Keywords: | Antisolvent precipitation Aqueous ethanol extract Boldine Boldo leaf antioxidants Bubble-point pressure Catechin Supercritical CO2 |
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