Experimental and theoretical investigation of proton exchange reaction between protic ionic liquid diethylmethylammonium trifluoromethanesulfonate and H2O

We investigated the possibility of proton exchange reaction between protic ionic liquid of diethylmethylammonium trifluoromethanesulfonate ([dema][TfOH]) and H2O by using NMR spectroscopy and theoretical calculation. NMR spectroscopy experiment showed that the proton exchange between [dema][TfOH] and H2O in a 1:1 M ratio occurred at room temperature. From the theoretical calculation, we found two reaction pathways for proton exchange between [dema][TfOH] and H2O. Both pathways have stepwise reaction with two transition states. After finishing the reaction along these pathways, the same complex structures of [dema][TfOH] and H2O are again formed, respectively. But the proton is exchanged between [dema][TfOH] and H2O.

Graphical abstractDownload high-res image (63KB)Download full-size imageHighlights► Proton exchange between dema-TfO and H2O is observed by NMR experiment. ► Several kinds of dema-TfO-H2O complex structures are found. ► Proton exchange reaction pathways are reported.