超臨界二酸化炭素抽出及び溶媒抽出における2-メチル-8-キノリノールによるパラジウム(II)の分配平衡への溶媒効果に関する研究

概要

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The solvent effect on the distribution ratio (D_M) of Pd(II) by extraction with 2-methyl-8-quinolinol (HMQ) was studied using supercritical CO_2 (SF-CO_2) and organic solvents, such as perfluoro-methylcy-clohexane, heptane, cyclohexane, carbon tetrachloride and benzene. From the experimental result on the slope of log D_M vs. HMQ concentration plot, the extracted species was determined to be Pd(MQ)_2. A linear relationship was observed in a plot of the distribution constant of HMQ (K_<D,HMQ) vs. the solubility parameter (δ) of the extraction medium based on regular solution theory in both the SF-CO_2 extraction (SFE) and the solvent extraction (SE) systems. The difference in the slope between the SFE and the SE systems is attributable to the extent of the specific interaction of the solute HMQ with the solvent molecules, i.e., CO_2 and the organic solvent molecules. The D_M vs. δ plot obtained under a given extraction condition using SF-CO_2 (11〜40 MPa) and organic solvents showed clear linearity. The D_M obtained using SF-CO_2 at a pressure range from 8.5 to 11 MPa was independent of the δ of SF-CO_2, which coincides with the experimental fact that the solubility of Pd(MQ)_2 in the SF-CO_2 at 8.5 to 11 MPa was practically constant.
社団法人日本分析化学会の論文
2005-01-05