Searching for molecular arene hydrogenation catalysis in ionic liquids

Applications of functionalized ionic liquids

“…Most functional groups can be introduced directly to the imidazolium moiety using these methods [43][44][45][46][47][48][49][50][51][52][53][54][55][56] . Fig.…”

Nanoheterogeneous Catalytic Hydrogenation of Arenes: Evaluation of the Surfactant‐Stabilized Aqueous Ruthenium(0) Colloidal Suspension

“…[2] Total hydrogenation has also industrial applications such as the conversion of benzene to cyclohexane, a key intermediate in adipic acid production, [3] the removal of aromatic compounds from fuels [4] which are responsible for health diseases. [5] Among the controversial active catalytic species, [6][7][8] soluble noble metal nanoparticles are considered as a reference catalyst in monocyclic arene hydrogenation under mild conditions and several stabilized systems have been largely reported. [1,9] The protective agent is chosen according to the "organic" or "aqueous" nature of the media which generally depends on the nature of the precursor, namely organometallic compounds or metals salts.…”

Hydrogenation in Ionic Liquids

“…An example of arene reductions by Rh nanoparticles supported on an ionic liquid-like co-polymer was reported by Zhao et al [31] In this case most of the intermediate dienes were found to be soluble in [bmim] [BF 4 ] which was used as a solvent, hence hydrogenation did not stop at the diene and further hydrogenated products predominate. Dyson et al [32] have also performed reductions of benzene, exploiting solubility differences using K 2 PtCl 4 /[N-octyl-3-picolinium][AlCl 4 ]. The group also put forward a mechanism to account for the superior activity of K 2 PtCl 4 (99 % yield of cyclohexane, at 100 °C, 50 bar H 2 in 240 mins) over other catalysts screened (Figure 4) in which a trimetal face is coordinated by the aromatic π-system of benzene.…”

“…For [bmim][NTf 2 ] the initial TOF decreased from 14.0 x 10 -2 s -1 (initial TOF for reaction without IL) to 7.2 x 10 -2 s -1 . Geldbach et al [32] investigated the generation of catalysts from metal chlorides in the Lewis acidic IL, [N-octyl-3-picolinium]AlCl 4 ( Figure 11), by dissolving a series of metal chlorides in the IL and adding benzene as the substrate. The hydrogenation of benzene to cyclohexane is an important petrochemical process and research in this area is in continuous evolution.…”

“…[123] Five different SILC (supported ionic liquid catalyst) compounds have also been used by Virtanen et al [124] to investigate the kinetics of citral hydrogenation ( Figure 50) and kinetic modelling was based on the LangmuirHinshelwood-Hougen-Watson concept for citral hydrogenation. Palladium nanoparticles in the IL layer were immobilised on an ACC and the results of the hydrogenation compared with conventional palladium on ACC (32). The bulk solvent used was n-hexane as no leaching of the IL was observed using this solvent, except in the case of [bmim] [BF 4 ].…”