Ionic liquids via reaction of the zwitterionic 1,3-dimethylimidazolium-2-carboxylate with protic acids. Overcoming synthetic limitations and establishing new halide free protocols for the formation of ILs

Heterogenously catalyzed one-step alkylation and carboxylation of N-methylimidazole with dimethyl carbonate in continuous flow

“…The abovedescribed process is applicable to the synthesis other N-based ILs, e.g., with piperidine or pyrrolidine cores. The anion metathesis could then be performed simply by titration with protic acids under mild conditions [19] . Carbon dioxide and methanol would constitute the only side products.…”

“…Reaction temperatures above 140 ° C should shift to the thermodynamically controlled substitution in the 4-position of the imidazole ring ( 3a ) [19] . As reported in literature, the non-catalyzed alkylation reaction is performed in low-volume autoclaves that require a high temperature and pressure as well as economically unacceptable long reaction times.…”

Ionic Liquids in Catalytic Biomass Transformation

“…This method uses dimethylcarbonate (DMC) as a clean methylating agent to substitute alkyl halides. It can prevent the formation of halide and other by-product that makes the ILs efficient [5]. The downside of this method is that it is restricted by the availability of the acid (HX) or NH 4 + salts.…”

“…Although a variety of methods have been reported for synthesizing ILs [5], the most commonly used procedures are summarized in Figure 5 and 6. (1) Path A: Metathetic exchange of anion.…”

Crystal structure of bis(1,3-dimethylimidazolium hydrogen sulfate) — 18-crown-6 (2:1), [C5H9N2]2[HSO4]2 · C12H24O6

“…Source of material 1,3-dimethylimidazolium hydrogensulfate, [DMIm][HSO4], was synthesized according to literature [1]. 18-Crown-6 (1.135 mmol, 300 mg) was added to [DMIm][HSO 4](1.03 mmol, 200 mg).…”