Synthesis of novel non-toxic naphthenic and benzoic acid ionic liquids. Structure-properties relationship and evaluation of their biodegradability potential

Abstract

Protic Ionic Liquids (PILs) are promising solvents with desirable physicochemical properties for a variety of applications. They are considered as greener alternatives to common organic solvents but in order to efficiently be characterized as green their environmental impact has to be assessed. In the present study, the design, synthesis and an initial potential hazard assessment of 11 naphthenic and benzoic acid based PILs is presented. PILs’ “greenness” is enhanced considering that they are non-toxic according to the aquatic toxicity evaluation and most of them show satisfactorily to extremely high biodegradability level. Moreover, two of their most important physicochemical properties, viscosity and glass transition temperature (Tg), were determined for selected ILs. The effect of the aromatic and alicyclic ring on the anions, the size and the presence of a hydroxyl substituent at anions and cations has been also discussed for the studied environmental and physicochemical properties.