CuCoMgAlO_x Mixed Oxides as Selective Catalysts for the Hydrogenation of Furan Compounds

Single phase CuCoMgAl-layered hydroxides were obtained by making fine adjustment to their composition through changing the (Co + Cu)/Mg = 0.5; 1; 2; 3 and Co/Cu = 0.5; 1; 2 ratios. The rise of Co/Cu in systems contributed to the increase in their thermal stability. CuCoMgAl-catalysts showed high selectivity of carbonyl group hydrogenation in furfural and 5-hydroxymethylfurfural. In furfural hydrogenation, the selectivity to furfuryl alcohol was more than 99%, and in 5-hydroxymethylfurfural hydrogenation, the selectivity to 2,5-hydroxymethyl furfural was 95%. The surface of the samples with different Co/Cu after calcination and reduction was the same and had a «core-shell» structure (TEM). «Core» consisted of Cu and Co metallic particles. «Shell» consisted of CuCoMgAlOx mixed no-stoichiometric spinel oxides. There was no sintering or change in size of the metallic particles after the reaction. For the sample with Co/Cu = 1, their phase composition after reaction remained unchangeable. The increase of Co/Cu led to the formation of an X-ray amorphous phase after the reaction. This suggests the decrease in structural stability of this sample. The obtained results prove the prospects of using bimetallic CoCu-systems for hydrogenation of furan aldehydes, and opens up new directions for further research and improvement

CoCuMgAl-Mixed-Oxide-Based Catalysts with Fine-Tunable Composition for the Hydrogenation of Furan Compounds

Catalysts based on CoCuMgAl mixed oxides were synthesized and studied in the hydrogenations of furfural and 5-hydroxymethylfurfural under different conditions. The changes in the structural properties of the catalysts at different stages of their preparation were studied using a set of physical methods (XRD, SEM, and TEM). It was shown that the fine regulation of the chemical compositions of the mixed oxides (i.e., changes in the Co/Cu ratio) made it possible to vary the structure, morphology, and catalytic properties of the samples. The phase composition of catalysts with Co/Cu = 1 did not change during the catalytic reaction, although the initial catalysts had a less-homogeneous morphology. 5-hydroxymethylfurfural conversion was higher for the samples with Co/Cu = 1. Furfural conversion increased when raising the Co/Cu ratio. The selectivity toward furfuryl alcohol for the catalyst with Co/Cu = 2 under mild conditions of furfural hydrogenation was more than 99%. The results obtained are important for the development of the scientific foundations of the preparation of hydrogenation catalysts with a fine-tunable composition in order to obtain the desired hydrogenation products

Mechanochemical Synthesis of Fine Carbide-Containing Catalysts for Hydroconversion of Heavy Oil Residues

Высокодисперсные молибден-карбидные каталитические системы были получены методом механической активации в инертной среде. Исследован состав, морфология и проведена оценка каталитического поведения молибден-карбидных систем в slurry-процессе гидропереработки гудрона, установлено, что в присутствии молибден-карбидного катализатора наблюдается снижение выхода кокса более чем в три раза по сравнению с содержанием кокса, полученного при тех же температурно-временных параметрах процесса без катализатораFine molybdenum-carbide catalytic systems were obtained by the method of mechanical activation in an inert atmosphere. The composition and morphology were investigated, the catalytic behavior of molybdenum-carbide systems was estimated in the hydrotreatment process of vacuum residue. In the presence of a molybdenum-carbide catalyst, a decrease in the coke yield by more than three times is observed compared to the coke content obtained with the same temperature-time parameters of the process without a catalys

Synthesis of CuAl-, CoAl-, and CuCoAl-Catalysts from Layered Hydroxides for Furfural Hydrogenation

Catalysts based on CuAl-, CoAl-, and CuCoAl-layered hydroxides with M2+/Al = 2 and Cu/Co = 1 molar ratio were obtained. The effect of amount of cobalt on the structural properties, morphology, surface cations distribution, oxide phase formation, thermal stability of the samples and reduction of metals from them was studied. The effect of reaction conditions (temperature, time, pressure, solvent) and conditions of preliminary treatment of catalysts on their catalytic properties in furfural hydrogenation was established. High selectivity to furfuryl alcohol was observed for all the samples irrespective of pretreatment and reaction conditions. The synergetic effect in furfural hydrogenation between Co and Cu in the CuCoAlOx catalysts was revealed when ethanol is used as a solvent