Aqueous functional group activity coefficients (AQUAFAC) 4: Applications to complex organic compounds

AQUAFAC is a group contribution scheme for the prediction of aqueous activity coefficients. When combined with the well known ideal solubility equation, AQUAFAC can be used to predict the solubility of a wide variety of organic compounds. This method has successfully predicted the aqueous solubility of simple hydrocarbons, halogenated hydrocarbons, and non-hydrogen bonding oxygen containing compounds, as well as some single hydrogen bonding compounds. In this report the AQUAFAC scheme is extended to include twenty-two new group contribution values. These values were obtained from 379 individual solubility values which represent 168 different organic nitrogen containing compounds. Regression of the observed versus predicted aqueous solubility for the new data set gives a root mean square error of 0.42 with a R2 of 0.95. Combining this with the previous data brings the AQUAFAC database to over 2700 individual measurements for over 1100 different compounds.