Using Mg‐Al Mixed Oxide and Reconstructed Hydrotalcite as Basic Catalysts for Aldol Condensation of Furfural and Cyclohexanone

Abstract This study presents results on aldol condensation of furfural and cyclohexanone in presence of Mg‐Al hydrotalcite‐derived materials as solid basic catalysts at reaction temperatures from 25 to 90 °C and a cyclohexanone to furfural molar ratio of 1–10. Mg‐Al mixed oxide exhibited reasonable activity with furfural conversion of ca. 50 % after 180 min of the reaction at T =90 °C. The activity of reconstructed hydrotalcite was much higher with furfural conversion close to 100 % at short reaction times. In comparison with Mg‐Al mixed oxide, the initial reaction rate has increased 30–50 times. Under similar reaction conditions, cyclohexanone self‐condensation on HTC‐derived catalysts could not compete with aldol condensation because the former reaction was inhibited by produced water. The change in CH/F molar ratio influenced both furfural conversion and product selectivity; higher furfural content in the reaction mixture favored the second condensation step.