Effect of Ni, La, and Ce Oxides on a Cu/Al₂O₃ Catalyst with Low Copper Loading for Ethanol Non‐oxidative Dehydrogenation

Abstract

The effect of modifying additives (Ni, La, Ce oxides) on the activity of Cu/Al2O3 with a low copper loading was studied for ethanol non‐oxidative dehydrogenation. The catalysts were prepared by impregnation of the commercial Al2O3 granules and characterized by Brunauer‐Emmett‐Teller (BET), scanning electron microscopy (SEM), temperature‐programmed desorption of NH3 (TPD‐NH3), temperature‐programmed reduction of H2 (H2‐TPR), and thermogravimetric analysis (TGA). Modification of Cu/Al2O3 with Ni, La, and Ce oxides results in increasing catalytic activity. A modification of the Cu/Al2O3 catalyst with nickel and lanthanum oxides, in contrast to cerium oxide, leads to an improvement in the dispersion of the catalyst particles. The Cu‐Ni/Al2O3 catalyst with the highest acidity has the highest selectivity for acetaldehyde. The highest selectivity for butanol is observed for the Cu‐La/Al2O3 catalyst, which has the lowest acidity.

Ethanol Dehydrogenation over Copper-Silica Catalysts: From Sub-Nanometer Clusters to 15 nm Large Particles

“…30 Finally, catalysts based on copper deposited on alumina and silica-alumina produce significant amounts of dehydration products (ethylene and diethyl ether) due to the acidity of the support. 19,31 Stable Cu/SiO 2 catalysts (500 h time-on-stream) were synthesized by the ammonia evaporation method, which provided highly dispersed particles, as already discussed. However, the authors mentioned that the number of available Cu sites in the stable catalysts exceeded the site requirement based on GHSV.…”

Ethanol Dehydrogenation over Copper-Silica Catalysts: From Atomic Distribution to 15 nm Large Particles

“…27 On the other hand, catalysts based on copper deposited on alumina and silica-alumina produce significant amounts of dehydration products (ethylene and diethyl ether) due to the acidity of the support. 19,28 Stable Cu/SiO2 catalysts (500 h time-on-stream) were synthesized by the ammonia evaporation method, which provided highly dispersed particles, as already discussed. However, the authors mentioned that the number of available Cu sites in the stable catalysts exceeded the site requirement based on GHSV.…”

Synthesis, Characterization of Magnetic Composites and Testing of Their Activity in Liquid-phase Oxidation of Phenol with Oxygen

“…A qualitative comparison of the obtained spectra of the reaction product shows the presence of CH in the aromatic ring and double C =C bonds, valence vibrations of C= O groups of carbonyl compounds, the band 3059 cm -1 corresponds to the presence of double C=C bonds, the band 3424 cm -1 may refer to vibrations of hydroxyl groups of the intermediate compound hydroquinone. The band in the region of 1678 cm −1 and the intense band in the region of 1646 cm −1 refers to fluctuations in the bonds of the C=O carbonyl group of benzoquinone [40][41][42][43][44][59][60][61][62]. The peaks of 1366 cm -1 and 1310 cm -1 may relate to fluctuations in the C-H and C-C bonds of the quinone ring (Fig.…”

“…When stabilized with polyethyleneimine, the reflex diffraction patterns revealed several phases of iron oxides -γ-Fe2O3, α-Fe2O3, ε-Fe2O3. The diffraction reflections for cobalt oxide correspond to spinel Co3O4 [37,38,42,[57][58][59][60]. 2 show the Mössbauer spectrum of composites obtained at room temperature belonging to iron oxides in a magnetically ordered state.…”

“…The shift of the absorption bands with respect to the PEI spectrum is observed, as well as the shift of the bands characteristic of the bonds of the NH group in the region of 1649 cm -1 . The complexity of the spectra in this area did not allow us to find out the participation of PEI in the formation of complexes with metal ions [51][52][53][54][55][56][57][58][59][60][61][62].…”