Influence of ionic liquid film thickness and flow rate on macrocyclization efficiency and selectivity in supported ionic liquid‐liquid phase catalysis

Supported ionic‐liquid phase (SILP) technology in a biphasic setting with n‐heptane as the transport phase was applied to the Ru‐alkylidene‐N‐heterocyclic carbene (NHC) catalyzed macrocyclization of α,ω‐dienes to elucidate the effect of ionic liquid (IL)‐film thickness, flow rate as well as substrate and product concentration on macrocyclization efficiency, and Z‐selectivity. To understand the molecular‐level behavior of the substrates and products at the n‐heptane/IL interphase, atomistic molecular dynamics simulations were conducted and correlated with experimental observations. The thickness of the IL layer strongly influences the Z/E ratio of the products in that a thin IL layer favors higher Z/E ratios by confining the catalyst between the pore wall and the liquid‐liquid interphase whereas a thick IL layer favors formation of the E‐product and Ru‐hydride catalyzed isomerization reactions. Also, macrocyclization efficiency, expressed by the ratio of oligomers/macromonocycle (O/MMC), is influenced both by the flow rate and the thickness of the IL layer.