以逆向流層析測量有機物在高壓流體和水中的分配係數

Abstract

以逆向流層析測量有機物在高壓流體和水中的分配係數 學生：張家耀 指導教授：余艇 國立交通大學應用化學研究所 摘要 近年來，一些人嘗試著利用超臨界二氧化碳萃取水中的有機物質，已經有不錯的成效。如果能事先知道不同實驗參數（溫度，壓力）下，有機物在超臨界二氧化碳和水中的分配係數（partition coefficient），可以有助於萃取的預測。傳統方法是先將有機物溶於水中，再利用攪拌器使超臨界二氧化碳和水在高壓容器中充分混合後，分別取出超臨界二氧化碳和水以紫外光/可見光檢測器或氣相層析儀測量溶於上述兩相中有機物濃度，以便計算分配係數。由於此種方法是利用批式(Batch)測量個別有機物的分配係數會較為耗時，並且因為無法直接線上偵測，因此步驟較多比較容易造成誤差，因而影響實驗的再現性。本實驗則是利用逆向流層析配合紫外光/可見光偵測器作線上偵測，以一次層析求得混合有機物的沖提體積再帶入分配係數的公式求得個別有機物的分配係數，這將提供一個便捷的測量方法並且顯示出不錯的再現性。 除了二氧化碳之外，由於1,1,1,2-Tetrafluoroethane(R-134a)具有類似有機溶劑的性質，而有層析及萃取上應用價值，因此本實驗也以高速逆向流層析測量有機物在冷媒R-134a和水中的分配係數。

Water-Compressed Fluids Partition Coefficient Measurements of Organic Solutes Using Countercurrent Chromatography Student:Jia-Yaw Chang Advisor:Tiing Yu* Institute of Applied Chemistry National Chiao Tung University Abstract Extraction of organic substances from aqueous solutions using supercritical fluid carbon dioxide (SF CO2) has drawn attentions. It helps to predict the recovery yields in applications if the partition coefficients are determined in advance. The partition coefficient was usually determined by placing the aqueous sample with SF CO2 in a high-pressure cell. After thorough mixing, the solutions of both phases were sampled in order to measure the solubilities of the organic compound in each phase. The partition coefficient could be calculated accordingly. We utilized a high-pressure countercurrent chromatography (CCC) system to determine the coefficients. Parameters that were used to calculate the coefficient, including the stationary phase-retention volume, the retention volume of the solute, and the dead volume, could be obtained by one chromatographic run. In addition to SF CO2, we also measured water-1,1,1,2-tetrafluoroethane partition coefficients of some organic compounds using commercialized high speed CCC. The partition coefficients of a group of organic compounds could be determined simultaneously when the aqueous sample of a mixture was separated in the CCC column. The experimental data showed very good reproducibility.