Optimization of the process conditions for minimizing the deactivation in the furfural-cyclopentanone aldol condensation in a continuous reactor

Abstract This work demonstrates the key role of salts (both anions and alkaline cations) in the activity and stability of Mg-Zr mixed oxide as catalyst for the furfural-cyclopentanone aldol condensation in a continuous fixed bed reactor. Reactants oligomers are shown to cause active sites blockage, controlling the reaction conditions being required to maximize the selectivity for the first condensation adduct. The best results were obtained at pH = 8, using KHCO3 for fixing this pH. At these conditions, 75 % and 14 % of C10 and C15 yields were observed at 8 h on stream, whereas experiments performed at the other conditions show almost total deactivation. This good performance (performance and stability) is explained by a synergistic effect of two phenomena: a good buffering activity of the anion, and the ion exchange involving Na and K, which leads to the stabilization of the basic sites.