Gas-Phase Hydroformylation Using Supported Ionic Liquid Phase (SILP) Catalysts – Influence of Support Texture on Effective Kinetics

Abstract

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.