Selectivity enhancement in the catalytic hydrogenation of propionitrile using ionic liquid multiphase reaction systems

Tuning the selectivity of ruthenium nanoscale catalysts with functionalised ionic liquids: Hydrogenation of nitriles

“…The present Ru-NPs do not show activity for arene hydrogenation, while other ILs Ru-NPs are active toward arene hydrogenation [12,18,19]. Additionally, the activation energy for toluene hydrogenation with ruthenium catalysts in IL is approximately 20% lower than the activation energy for hydrogenation of nitrile groups in ILs [8,12]. These results strongly indicate that the presence of the nitrile group in the IL side-chain influences the interaction between the Ru-NP surfaces and a corresponding substrate.…”

“…Herein, we report that the catalytic surface properties of ruthenium nanoparticles in ILs can be tuned by the use of nitrile containing ligand/substrates. In particular, a clean hydrogenative coupling reaction of benzonitrile by aminolysis to provide (E)-N-benzylidene-1-phenylmethanamine takes place without arene hydrogenation [8].…”

Grignard Reactions in Pyridinium and Phosphonium Ionic Liquids

“…[10] In some cases little difference can be observed between reactions carried out in ILs and traditional organic solvents, but in others the IL has a substantial effect on reaction rate, yield and selectivity. [11] The most widely studied ILs are based on the imidazolium cation. These compounds can form N-heterocyclic carbenes 942 was the favored pathway when reactions were conducted in pyridinium ILs 10a, b in the absence an ethereal co-solvent.…”

Hydrogenation in Ionic Liquids

“…Additionally the activation energy for toluene hydrogenation with the ruthenium catalyst in IL is approximately 20 % lower than the activation energy for hydrogenation of nitrile groups in the ILs. [69,114] They found that the selectivity is dependent on the IL support and not on the Ru nanomaterial. For the hydrogenation of benzonitrile to (E)-N-benzylidene-1-phenylmethanamine, via displacement of ammonia, their hypothesis is that the strong coordination of the nitrile group to the ruthenium surface prevents displacement by the aromatic ring of benzonitrile.…”

“…The process was shown to be suitable for recycling procedures, with no significant reduction in TOF being observed after four recycles. Based on the assumption that the efficiency of CO 2 hydrogenation would increase if the IL contained more than one basic group, Zhang [68] Obert et al [69] used a ruthenium on carbon catalyst for the selective hydrogenation of propionitrile to propylamine under biphasic reaction conditions. In 1998 Dow Chemical Co. patented a process for this hydrogenation using a biphasic system of water and organic solvent where selectivities towards propylamine of > 80 % were achieved.…”