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Novel ammonium, phosphonium and imidazolium ionic liquids (ILs) based on levulinic acid as the anion were prepared and characterized (NMR spectroscopy, FT-IR spectroscopy, TGA, and viscosity). Commercial methyl carbonate precursors were employed to access the target levulinate ILs via a quick, one-step synthetic procedure that does not require the use of halogenated solvents or produce any waste water. The ability of the levulinate ILs to dissolve cellulose was investigated in detail. Provided the right conditions are employed, these ILs display good to remarkable dissolution ability toward their parent polysaccharide. In particular, [EMIM][Lev] is able to dissolve 29 wt% cellulose at 100 °C, which increases to 38 wt% under reduced pressure. For the best performing IL, several variations of the dissolution conditions, which are known to prevent potential side reactions of the imidazolium cation, have also been tested. The ecotoxicity of the prepared ILs as well as of the previously reported protic levulinate ILs has also been assessed by means of both freshwater and seawater model organisms belonging to different steps of the trophic chain. [ABSTRACT FROM AUTHOR]

Two new levulinate-based protic ionic liquids (Lev PILs) have been synthesized through an easy, scalable neutralization reaction between levulinic acid (LA), which is one of the most promising renewable building blocks obtainable from cellulose, and amidine superbases (either DBU or DBN). The prepared PILs have been characterized (by means of NMR, FT-IR, TGA and viscosity measurements) and studied as potential cellulose dissolution media. These species display a dissolving ability (weightcellulose/weightPIL) comparable with the popular, and to date best performing, acetate-based PILs. In contrast with these systems, Lev PILs are composed of a larger renewable anion (levulinate vs. acetate): this allows for a reduced amount of the expensive non-renewable superbase cation component while only slightly affecting the cellulose dissolution performance. An application of the proposed Lev PILs, namely the levulination of cellulose, has also been studied. The impact of various reaction parameters (i.e. temperature, amount of anhydride, amount of co-solvent) on the reaction outcome and on the functionalization degree (up to 1.87) has been studied. γ-Valerolactone, a renewable green solvent which is in turn prepared from LA, has been found as an effective DMSO replacement when used as co-solvent for the reaction, allowing for satisfactory functionalization degrees. [ABSTRACT FROM AUTHOR]