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Pyroaurite‐based MgFe mixed oxides and their activity in aldol condensation of furfural with acetone: effect of oxide composition

Kocík, Jaroslav, Frolich, Karel, Perková, Ilona, Horáček, Jan
Journal of chemical technology and biotechnology 2019 v.94 no.2 pp. 435-445
Lewis acids, acetone, catalytic activity, condensation reactions, furfural, magnesium, oxides, porous media, statistical analysis
BACKGROUND: Pyroaurite‐based MgFe oxides with varying Mg:Fe ratio were studied. The structural and acido‐basic properties were examined by number of experimental techniques. The oxide properties were correlated with the catalytic activity in aldol condensation of furfural with acetone. RESULTS: Well‐developed mesoporous structure was detected for all oxides. Peculiar continuous increase of concentration of basic sites and population of unsaturated strong basic O²⁻ sites was observed with the rising amount of magnesium in the MgFe oxide matrix. A relatively higher concentration of Lewis acid Meⁿ⁺ sites was shown for low Mg:Fe ratios. Unambiguous correlation between conversion of furfural and the density of strong basic sites was proved by combined catalytic and statistical analysis. The contribution of other basic sites was found significantly less important. The impact of both acid and basic sites on the composition of reaction products was discussed. CONCLUSIONS: MgFe oxides revealed good catalytic performance in the aldol condensation of furfural with acetone where samples with a high Mg:Fe ratio were significantly more basic and had relatively enhanced furfural conversion (nominal Mg:Fe ratio 10; furfural conversion 88% and selectivity to F₂Ac 34%; reaction conditions: batch reactor; 50 °C; acetone/furfural = 10 mol L–¹). © 2018 Society of Chemical Industry