Predicting the Distribution Constants of Butane Extraction of Organic Pollutants from Aqueous Solubility

Abstract

The n‐butane/water distribution constant is one of the key parameters in determining the extraction efficiency. Experimental results on 34 organic compounds illustrated that a fundamental linear relationship exists between the distribution constant and the aqueous solubility of the solute. The relationship can be broadly applied to many different classes of chemical compounds as well as to many different solvent extraction systems. The linear equation obtained by a regression method allows one to estimate the distribution constant and predict the result of butane extraction if the aqueous solubility of certain solute is available.

The Correlation and Prediction of Butane/Water and Gas/Butane Partition Coefficients

“…Correlations for butane/water and gas/butane partition coeffi cients have been constructed for 43 varied compounds. The correlation for butane/water partition coeffi cients is more general than those described before (Teo et al, 2002) because it includes a number of gaseous compounds as well as several alkanes. The correlation for gas/butane partition coeffi cients appears to be the fi rst such correlation reported.…”

“…T he partition coeffi cients of butane extraction of organic nonelectrolytes from aqueous solution have recently been obtained (Teo et al, 2002), and useful equations have been reported that correlate the partition coeffi cients, as log Pbut, with aqueous solubilities, as log Sw with Sw in units of mmol/L or mg/L: (2), it is then possible to determine removal effi ciencies for organic nonelectrolytes from water by extraction with butane (Teo et al, 2000;Yang et al, 2004). One major diffi culty in using these equations to predict butane/water partition coeffi cient, is the requirement of determined solubilities in water.…”

“…Before applying Equation (3) to the available log Pbut values Pbut values Pbut (Teo et al, 2002), we thought it useful to correlate the log Pbut values against those for partition from water to another alkane. Partition coeffi cients for all the compounds studied in the butane/water system were not available in any given alkane/ water system, and so we calculated log P values for all the P values for all the P compounds used (Teo et al, 2002), in a typical alkane/water system, namely hexane/water, and compared these with the known log Pbut values. The necessary descriptors for the various Pbut values.…”

“…Although Equation (4) is of similar goodness-of-fi t to Equation (1) and Equation (2), we do not advocate it as a predictive method. We use it only to identify any marked deviant compounds in the butane/water set (Teo et al, 2002), For all 34 compounds, application of Equation (3) resulted in a reasonably good equation:…”