Process intensification is a cornerstone to achieve a significant reduction in energy consumption and CO2 emissions in the chemical industry. In this context, a monolithic membrane reactor combining homogeneous catalytic...

Supported ionic liquid phase (SILP) catalysts are an extremely promising class of materials that combine advantageous concepts from both homogeneous and heterogeneous catalysis. Optimized SILP catalysts should exhibit a thin, homogeneous, and continuous film of the ionic liquid (IL) to avoid pore blocking and to ensure a good accessibility of the catalyst. Yet, the interactions between the IL and the support, which determine the formation of such a film, are still poorly understood. We investigate here in a systematic way the deposition of three imidazolium-based ILs on silica supports with different surface areas and morphologies using 1 H magic angle spinning solidstate nuclear magnetic resonance spectroscopy. We demonstrate that the point of complete surface wetting can be determined by the disappearance of the 1 H resonance of isolated silanol groups and that this point depends both on the textural properties of the support material and the chemical properties of the IL. 1 H chemical shifts also provide valuable insight into hydrogen bonding interactions within the IL and between the IL and the support. They indicate cleavage of the anion−cation hydrogen bonds upon IL deposition and the formation of new hydrogen bonds with the silica surface.

The supported ionic liquid phase (SILP) concept, which included thin films of ionic liquid dispersed onto porous support surfaces, was applied for the gas‐phase hydroformylation of but‐1‐ene catalyzed by Rh‐bpp (bpp=biphephos ligand) complexes. The support material silica was carefully pre‐treated by a hydrothermal procedure to induce textural changes concerning the pore size. Starting with a mean pore size of 3 nm these could be enlarged by almost a factor of 10 up to 27 nm. Different particle size fractions having the same pore size of 10±1 nm were investigated regarding the hydroformylation activity. A clear limitation by pore diffusion can be found for particles larger than 500 μm in diameter. The limitation could be minimized by enlarging the pore size. To support the data, dimensionless numbers and criteria were calculated, including Thiele‐modulus, Mears, and Weisz‐Prater. All data support the assumption that limitation occurs around 500 μm particle size if 10 nm pores are present.