ABSTRACT
In the present work, nanocrystalline Zn-MOF-74 is shown to be a heterogeneous catalyst for the acid-catalyzed ring-opening alcoholysis of cyclohexene oxide. The results corroborated that accessible open metal sites within the material are critical conditions (Zn(ii) Lewis acid sites) for this reaction. Zn-MOF-74 was tested at three different temperatures (30, 40, and 50 °C) for the alcoholysis reaction. Furthermore, the cyclohexene oxide conversion was 94% in less than two days. A comparison of the catalytic activity with different crystal sizes of Zn-MOF-74 and the homogenous phase, zinc acetate, was conducted. Zn-MOF-74 exhibited excellent catalytic cyclability for three cycles without losing its activity. The material showed chemical stability by retaining its crystalline structure after the reaction and cyclability process.
ABSTRACT
This investigation deals with NiMo-alumina hydrotreating catalysts effective in the deoxygenation of rapeseed oil. The main goal was to compare catalyst structure and their deoxygenation performance and to link these parameters to reveal important structural information regarding the catalyst's intended use. Catalysts were prepared from different precursors (nickel acetate tetrahydrate/molybdenyl acetylacetonate in ethanol and water vs. nickel nitrate hexahydrate/ammonium heptamolybdate tetrahydrate in water), which resulted in their contrasting structural arrangement. These changes were characterized by elemental composition determination, UV-Vis diffuse reflectance spectroscopy, temperature programmed reduction by hydrogen, nitrogen physisorption at 77 K, scanning and transmission electron microscopies, and deoxygenation of rapeseed oil. The critical aspect of high oxygen elimination was a homogeneous dispersion of NiO and MoO3 phases on the support. It subsequently led to the effective transformation of the oxide form of a catalyst to its active sulfide form well-dispersed on the support. On the other hand, the formation of bulk MoO3 resulted in the separate bulk phase and lower extent of sulfidation.
