ABSTRACT
Heterogeneous catalysis is an important area of research that generates data as intricate as the phenomenon itself. Complexity is inherently coupled to the function of the catalyst and advance in knowledge can only be achieved if this complexity is adequately captured and accounted for. This requires integration of experiment and theory, high data quality and quality control, close interdisciplinary collaboration, and sharing of data and metadata, which is facilitated by the application of joint data management strategies. This Viewpoint Article first discusses the potential of a digital transition in catalysis research. Then, a summary of the current status in terms of data infrastructure in heterogeneous catalysis is presented, defining the various types of (meta-) data, from catalyst synthesis to functional analysis. Finally, an already implemented working concept for local data acquisition and storage is introduced and the benefits and further development directions for catalysis data use and sharing are discussed.
ABSTRACT
A niobium doped high surface aluminium fluoride (HS-AlF3) catalyst was prepared, using an approach in which niobium doped aluminium hydroxide fluoride obtained via reaction of aqueous HF with the respective metal alkoxides in isopropanol is further fluorinated under flow of CHClF2 at 200 °C. A comparable procedure was used to synthesize a Nb-free variant for comparison. Both catalysts exhibit very strong Lewis acidic surface sites which are capable to activate strong carbon-halogen bonds at room temperature, just as the classical high-surface AlF3 (HS-AlF3), obtained by reacting aluminium isopropoxide with anhydrous HF, does. The catalysts were characterized by elemental analysis, P-XRD, MAS NMR spectroscopy, N2 adsorption, NH3-TPD, and pyridine photoacoustic FT-IR spectroscopy. In contrast to previously reported niobium doped HS-AlF3, which was prepared using anhydrous HF, the doped catalyst obtained via this aqueous HF-route shows excellent performance both in the isomerization of 1,2-dibromohexafluoropropane, a reaction that occurs only in the presence of the strongest Lewis acids, and in the cyclization of citronellal to isopulegol, a reaction which requires both, Lewis and Brønsted acid sites.
ABSTRACT
Aluminium chlorofluoride (ACF) and high-surface aluminium fluoride (HS-AlF3) were analyzed by a set of characterization methods to assess their acidic properties: NH3-TPD, CO adsorption followed by DRIFTS, CD3CN-PAS-FTIR and MAS NMR spectroscopy after 15N-pyridine adsorption. Both catalysts contain very strong and medium-strong Lewis acid sites as confirmed by CO adsorption, in which small differences arise from the morphological properties of each catalyst, with ACF being microporous and HS-AlF3 mesoporous. Shifts of the CO vibration band of up to 77 cm-1 were observed, which account for very strong Lewis acid sites. In addition, very strong Lewis acid sites could be identified by CD3CN-PAS for both catalysts, exhibiting a shift of 95 cm-1 from free nitrile, the highest ever reported for a solid Lewis acid.
