Efficiency of fluorinated alcohol for extraction of organic acid from its dilute aqueous solution: A molecular optimization study of extractant

Abstract

Abstract The quantum chemical parameters of fluorinated octanol, such as charge distribution, molecular electrostatic potential and frontier molecular orbital have been investigated through quantum chemistry calculation by DFT method using the B3LYP level with the standard 6-311++G(d,p) basis set. In first step the natural population analysis (NPA) and molecular electrostatic potential (MEP) methods were applied to determine the reactive site of fluorinated octanol. In second step comparative analysis of frontier molecular orbital energy gaps of fluorinated octanol and benzoic acid was used to investigate the effect of fluorinated substitutional degree on benzoic acid extraction behavior of fluorinated octanol. The calculated results suggested that the reactive site is localized on the oxygen atom and the electron donor strength of the oxygen atom decreases with the increase of the fluorinated substitional degree due to the electron-withdrawing of fluorous group. 1 H ,1 H ,2 H ,2 H -perfluoro-1-octanol and 5,5,6,6,7,7,8,8-nonafluoro-1-octanol were selected as the extractants to testify the proposed theory. According to the prediction, the extraction capability on benzoic acid by 1 H ,1 H ,2 H ,2 H -perfluoro-1-octanol is lower than that of 5,5,6,6,7,7,8,8-nonafluoro-1-octanol at room temperature. The experimental results are in agreement with the corresponding theoretical data.