ABSTRACT
The reactivity of Mg-Fe mixed oxides obtained from hydrotalcite-like precursors in m-cresol alkylation with methanol was studied, and compared with that of MgAl mixed oxides. Samples were characterized using CO2 adsorption and ThermalProgrammed-Desorption (TPD) technique to obtain information on the relationship between surface properties and catalytic performance. The Mg-Fe mixed oxides were found to be less basic than the reference Mg-Al mixed oxide. Particular features of Fe-containing catalysts, such as (i) high selectivity towards C-alkylated products rather than O-alkylated products, (ii) formation of side-chain alkylated products (mainly thymol) and (iii) the high amount of heavy compounds obtained, were explained by hypothesizing a synergic contribution of acid and basic centers, which affected the reaction pathway. Tuning the composition of MgO-based mixed oxides makes it possible to control the catalytic performance in alkylation reactions of phenol derivatives with methanol.
