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利用固定体积可视高压釜测量出的在323K~353K温度范围内的CO2与2-丁醇二元体系在高压下的汽液相平衡数据,根据Krichevsky-Kasarnovsky方程建立了CO2在液相中的溶解度模型,得到了该二元体系在高压下的亨利系数和CO2在无限稀释溶液中的偏摩尔体积等性质。同时根据偏摩尔体积性质和Peng-Robinson状态方程及Van der Waals-2混合规则来计算该体系在平衡状态下的气、液相的偏摩尔体积。结果表明CO2在2-丁醇中的亨利系数和CO2在无限稀释溶液中的偏摩尔体积均为温度的函数,CO2在2-丁醇中的亨利系数随温度的升高而降低。CO2在无限稀释溶液中的偏摩尔体积∞1V在研究温度下均为负值,其中随温度升高,其绝对值下降。在平衡状态下的气、液相的偏摩尔体积计算结果表明:平衡状态下,液相中CO2与2-丁醇的偏摩尔体积均为正值。气相中不同温度下CO2的偏摩尔体积均为负值,且其绝对值随着压力的增加而越来越大,2-丁醇的偏摩尔体积均为正值。此研究为该体系超临界萃取条件的确立和指导工业化生产提供了理论依据。
The vapor-liquid equilibrium data of CO2 and 2-butanol binary system under high pressure in the range of 323K ~ 353K measured by a fixed-volume visual autoclave were used to establish the vapor-liquid equilibrium data of CO2 in the liquid phase according to the Krichevsky-Kasarnovsky equation Solubility model, the Henry’s coefficient of the binary system under high pressure and the partial molar volume of CO2 in infinite dilute solution were obtained. At the same time, the partial molar volumes of gas and liquid phases at equilibrium were calculated according to the properties of partial molar volume, Peng-Robinson equation of state and Van der Waals-2 mixing rule. The results show that the Henry’s Coefficients of CO2 in 2-butanol and the partial molar volumes of CO2 in infinite dilute solutions are both temperature functions. The Henry’s Coefficient of CO2 in 2-butanol decreases with increasing temperature. The partial molar volume of CO 2 in an infinite dilution solution ∞1V is negative at the study temperature, and its absolute value decreases with increasing temperature. The calculated partial molar volumes of gas and liquid in the equilibrium state show that the partial molar volumes of CO2 and 2-butanol in the liquid phase are both positive at equilibrium. The partial molar volume of CO2 at different temperatures in the gas phase is negative, and its absolute value increases with the increase of pressure. The partial molar volume of 2-butanol is positive. This study provides a theoretical basis for the establishment of the supercritical extraction conditions of this system and the guidance of industrialized production.