Bubble-point measurements for the system CO2 + aqueous ethanol solutions of boldo leaf antioxidant components (boldine and catechin) at high pressures
- 作者：Juan C. de la Fuente ; Gonzalo Nú ; ñ ; ez ; José ; M. del Valle
- 关键词：Antisolvent precipitation ; Aqueous ethanol extract ; Boldine ; Boldo leaf antioxidants ; Bubble-point pressure ; Catechin ; Supercritical CO2
- 刊名：Fluid Phase Equilibria
- 出版年：2007
- 期刊代码：32_03783812
- 类别：ce
- 出版时间：1 October 2007
- 卷：259
- 期：1
- 页码：77-82
- 文件大小：188 K
摘要
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 c;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.