Hybrid Molecular QSAR Model for Toxicity Estimation: Application to Ionic Liquids

Ionic Liquids have been suggested as one of the main possibilities to avoid solvent losses in chemical processes, but toxicity needs to be evaluated before technical applications. A quantitative structure-activity relationship (QSAR) based on a hybrid molecular QSAR model has been applied to the modeling of the aquatic ecotoxicity (Vibrio fischeri EC50) of ionic liquids. In this work, the ionic liquids database has a number of 96 data, which has been improved using data from the literature and experimental data following the UNE EN ISO 11348-3 procedure; these data involve nine different cations and seventeen anions, thus, 9×17=153 different combinations can be considered. The range of ecotoxicity covered by the novel QSAR corresponds to: Log EC50 values from -0.23 to 5.00. The modeling has been performed using mechanistic and stochastic considerations, hybrid model. The influence of the anion, cation and substitutions in the ecotoxicity has been estimated to design ionic liquids with lower toxicity, giving the pTS and N(CF3)2 anions and the imidazolium cation the lowest aquatic toxicity (statistically shown).