T. Méndez-Morales

The proper selection of solvents for biomass upgrading is a crucial task as it should carefully balance the enhancement of reactivity with a facile product recovery. A challenging case is the conversion of glucose and fructose to 5‐hydroxymethylfurfural (HMF). Ionic liquids (ILs) are often employed to boost the activity and selectivity of this process, although the isolation of HMF from the medium remains a major drawback. To investigate such solvent effects in a realistic (dynamic) environment, classical molecular dynamics (MD) simulations of HMF are performed in imidazolium‐based ILs with different anions. Several parameters are identified that directly control HMF–anion interactions, which may hamper product separation, as well as HMF–HMF contacts, which can promote undesired side‐reactions. These computational results would guide future high‐throughput screenings of new and improved IL media.

The mechanism of charge transfer between metal ions and graphene in the presence of an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) is investigated by means of density functional theory calculations. For that purpose, two different comparisons are established: (i) the behavior of Li+ and K+ when adsorbed onto the basal plane of graphene and (ii) the differences between Li+ approaching the carbon surface from the basal plane and being intercalated through the edge plane of trilayer graphene. In the first case, it is found that the metal ions must overcome high energy barriers due to their interaction with the ionic liquid before reaching an equilibrium position close to the interface. In addition, no significant charge transfer between any of the metals and graphene takes place until very close energetically unfavorable distances. The second configuration shows that Li+ has no equilibrium position in the proximity of the interface but instead has an equilibrium position when it is inside the electrode for which it has to cross an energy barrier. In this case, the formation of a LiC12 complex is observed since the charge transfer at the equilibrium distance is achieved to a considerable extent. Thus, the interfacial charge transfer resistance on the electrode in energy devices based on ionic liquids clearly depends not only on the binding of the ionic liquid to the metal cations and their ability to form a dense solvation shell around them but also on the surface topography and its effect on the ion packing on the surface.