Júlia Fütyű, Dávid Ispán, Csaba Fehér, Ágnes Szegedi, Tatjána Juzsakova, Jenő Hancsók, Rita Skoda-Földes
Molecular Catalysis, 2022, 518, 112075., https://doi.org/10.1016/j.mcat.2021.112075
Brønsted acidic ionic liquids with different type of cations (pyridinium, morpholinium, pyrrolidinium, imidazolium), N-sulfoalkyl chain length and different anions (triflate, hydrogensulfate and tetrafluoroborate) were prepared and immobilised on silica by adsorption. The ionic liquids were characterised by NMR and IR. Surface properties and Brønsted/Lewis acidity of the supported catalysts were also determined. Their catalytic activity and recyclability were compared in the oligomerisation of isobutene to obtain products that can be used as jet fuel blending components after hydrogenation. The results proved that imidazolium ionic liquids can be replaced by less toxic non-aromatic versions without any loss in their activity and stability. By the introduction of shorter sulfoalkyl chain into the cation, excellent results could be obtained even under milder conditions (lower temperature and shorter reaction time). Catalytic activity was shown to correlate to the Brønsted acidity of the catalyst.