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In this study, Mg-Fe catalysts with various molar ratio (Mg/Fe 1:1-10:1), prepared by calcination and subsequent rehydration of hydrotalcite structures, were characterized, tested and evaluated as suitable catalysts for the aldol condensation of furfural with acetone. XRD analyses confirmed that the layered structure was completely restored by rehydration in the catalysts with Mg:Fe molar ratio 3:1 and 4:1. TPD-CO2 showed that the catalysts of this molar ratio had the highest basicity. Rehydrated Mg-Fe catalysts were tested in aldol condensation carried out in a glass batch reactor at 60 °C, atmospheric pressure, 2 wt% of catalyst and acetone/furfural molar ratio 10:1. The catalysts with Mg/Fe molar ratio of 3:1 and 4:1 showed total furfural conversion. As high basicity causes a high activity of the catalyst, our results suggest that the rehydrated mixed oxides with molar ratio 3 to 4:1 were promising new catalysts for the aldol condensation of furfural with acetone.

Sulfur-free molybdenum carbides have the potential to replace the conventional sulfided catalysts used for hydrotreating. For these catalysts, it is not necessary to add sulfur to maintain their activity. This fact makes it worthwhile to continue working on improving their hydrotreating efficiency. According to our previous studies, the addition of Co or Ni promotes the hydrotreating activity, but only significant in the case of hydrodesulfurization efficiency (up to 30%). To increase the hydrodenitrogenation efficiency, other promoters, such as phosphorus, can be added. However, most of the published studies do not focus on co-processing or only on hydrotreating of gas oil model molecules at a laboratory scale. In this paper, we build on our previous research by studying five sulfur-free phosphorus-modified MoCx/Al 2 O 3 catalysts (0.5, 1.5, 2.5, 3.5, and 4.5 wt %) for the hydrotreating of atmospheric gas oil and co-processing with rapeseed oil (5, 10, and 25 wt %) under industrial conditions (330-350 °C, 5.5 MPa, WHSV 1-2 h -1 ). A phosphorus content up to 1.5 wt % promoted the hydrodesulfurization (5-10%) and the hydrodenitrogenation (10-25%) efficiencies of catalysts. Moreover, the triglycerides addition did not significantly decrease the catalyst activity during co-processing. Therefore, our results enable us to define the range of phosphorus addition that enhances MoCx activity using industrial conditions and commercial feedstocks, pointing the way to develop a suitable and sulfur-free alternative to conventional hydrotreating catalysts., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)