The Effects of SCILL Catalyst Modification on the Competitive Hydrogenation of 1‐Octyne and 1,7‐Octadiene versus 1‐Octene

Abstract

Competitive hydrogenation of mixtures of related unsaturated compounds remains a challenging problem. Recently, solid catalysts with an ionic liquid layer (SCILL) have shown potential for increased catalyst selectivity under batch conditions. Our results for the continuous flow competitive hydrogenation of 1‐octyne and 1,7‐octadiene versus 1‐octene with a nickel SCILL catalyst indicate improved catalyst selectivity under trickle bed conditions. Different ionic liquids ([MMIM][MeOSO3], [MMIM][OcOSO3], [MMIM][NTf2], [MePsec‐Bu3 ][MeOSO3], and [Et3S][NTf2]; MMIM=1,3‐dimethylimidazole and Tf=trifluoromethanesulfonyl) with varying catalyst loadings were investigated. The results highlight the importance of potential site‐specific interactions by the ionic liquid. They also indicate the importance of the cation for these effects.

Effects of Organic Modifiers on a Palladium Catalyst in the Competitive Hydrogenation of 1‐Octene Versus Octanal: An Evaluation of Solid Catalysts with an Ionic Liquid Layer

“…To determine the effects of the modifiers in question on the competitive hydrogenation between 1‐octene and octanal, the performance of the uncoated (no ionic liquid) catalyst at different iso‐conversion points was first established. For the purpose of this discussion, iso‐conversion is defined as the constant conversion attained once steady state has been achieved in a continuous‐flow reaction 9a. Typical reaction profiles at 40 % conversion of octanal and 1‐octene are shown in Figure 2.…”

“…However, it is still unknown to what relative extent transport effects (if any) and crystallite modification effects contribute to the SCILL catalyst behaviour. Diffusion effects have been claimed to have no effect,9d however, the idea that diffusion effects do not play any role has been challenged 9a. c In addition, no relation or comparison has been made with traditional organic catalyst modifiers such as pyridine.…”

Preparation of Catalytic Materials Using Ionic Liquids as the Media and Functional Components

“…In the monofunctional catalysts, the IL layer itself is not active for reaction, but the interaction of the ILs with solid support and the metal clusters can influence the activity and selectivity of the catalysts. However, the use of monofunctional catalysts are generally limited to hydrogenation . For instance, a catalyst was prepared by coating a commercial nickel catalyst with an IL [Bmim][n‐C 8 H 17 OSO 3 ] up to an IL loading of 20 wt% and used for the liquid‐phase hydrogenation of cyclooctadiene.…”

SCILLs as selective catalysts for the oxidation of aromatic alcohols

“…Alternatives to SILP for generating heterogeneous catalysts correspond to the anchoring of IL to the surface via a covalent bond (the SILC concept) [31] or to coating the IL on a support by physisorption (the Solid Catalyst with Ionic Liquid Layer, SCILL concept) [32][33][34]. To date, SCILL has been reported in selective catalytic hydrogenations including citral to citronellal [35], limonene to p-menthene [36] under supercritical CO2 conditions, propyne to propene [37] and of a 1-octene/1-octyne mixture [38]. In addition, it has been used to catalyse isomerizations [39].…”