A novel approach to tremendously influence the gas adsorption behavior of heterogeneous metal catalysts consists of adding a small quantity of an ionic liquid during the catalyst synthesis yielding a supported catalyst with an ionic liquid layer (SCILL). Herein, SCILL-type catalysts derived from silica-supported palladium were characterized by means of ICP-OES, TPR, X-ray absorption spectroscopy (XANES/EXAFS), X-ray photoelectron spectroscopy (XPS), hydrogen pulse chemisorption, and differential scanning hydrogen adsorption calorimetry. EXAFS analysis of SCILL-type palladium catalysts did not indicate significant changes in the bulk properties of Pd compared to untreated Pd/SiO 2 , the results are in good agreement with metallic Pd. XPS analysis revealed a more oxidized Pd surface if Pd/SiO 2 was treated with ionic liquids. In the case of [BMIM][N(CN) 2 ], Pd(II) species were present in part indicating a complexation of palladium by [N(CN) 2 ] -. Hydrogen uptakes determined by pulse chemisorption varied between 38 and 609 µmol g Pd -1 depending on the chosen IL, IL content, and temperature and were decreased in comparison to Pd/SiO 2 without IL. The initial heats of hydrogen adsorption were also affected in the presence of ionic liquids and were lowered compared to those of the untreated Pd/SiO 2 . Mechanisms showing how the ionic liquids interact with the active palladium site are proposed and might be in summary interpreted as a ligand effect by the ionic liquid similar to the influence of second metals in bimetallic catalysts.

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Conventional supported heterogeneous palladium catalysts in combination with a dicyanamide based ionic liquid are highly active with excellent selectivity in enabling the one-pot synthesis of citronellal through citral hydrogenation.

This study undertakes the design of hierarchically structured zeolites for the synthesis of methylenedianiline (MDA) mixtures via the liquid-phase condensation of aniline with formaldehyde. Affordable acid and base treatments enabled the controlled generation of an auxiliary network of intracrystalline mesopores within commercial zeolites of different frameworks, among which the FAU topology is identified as superior. As the micropore structure of the zeolite can be preserved, the unique shape selectivity is retained while improved mass transport in the hierarchical crystals leads to a 7-fold increased activity and a 3-fold prolonged lifetime before thermal regeneration is necessary. The linear correlation between the MDA yield and the product of the Brønsted acidity and the external surface area emphasizes the need to balance acid site and pore quality in the design of an optimal catalyst. Hierarchical USY zeolites outperform the state-of-the-art delaminated zeolites and mesoporous aluminosilicates. These results offer a viable solution for the replacement of the industrially applied homogeneous catalyst (HCl), resulting in an efficient and environmental friendly technology for the production of polyurethanes.