超临界CO_2-溶质二元系的密度及溶质的偏摩尔体积

Densities of CO_2-Ethanol, CO_2-Acetone, CO_2-n-Heptane Binary Mixtures and Partial Molar Volumes of the Solutes

在308．15和318．15K温度下，80－170bar压力范围内，测定了CO2-乙醇、CO2-丙酮和CO2-正庚烷混合物的密度，溶质的浓度范围是0－1．3mol·L－1．在此基础上，计算了溶质的偏摩尔体积，系统地研究了温度、压力和溶质浓度对二元混合物密度的影响，并从压力和溶质浓度对溶质偏摩尔体积影响的角度研究体系中的分子间相互作用．

The densities of CO2-ethanol, CO2-acetonc and CO2-n-heptane binary mixtures were measured at 308. 15 K and 318.15 K and under pressures ranging from 80 to 170 bar. The concentrations of the solutes (alcohol, acetone, and n-heptane)were form O to 1.3 mol·L-1. The partial molar volumes of the solutes at 318.15k were calculated based on the relationship between the densities of the mixtures and the concentrations of the solutes. It was observed that the partial molar volumes of all the three solutes are negative and the absolute value decreases with the pressure and the concentration of the solute.