Preparation of succinic acid pillared S₂O₈^2-/Mg-Al hydrotalcites and their application in cyclohexanone self-condensation

A series of solid catalysts with high conversion performance and excellent selectivity for cyclohexanone self-condensation were developed. S₂O₈^2-/Su-MgAl hydrotalcites were prepared by impregnation and reconstruction methods and their structures were characterized by XRD, FT-IR, BET and SEM. The results show that no significant structural change of LDH was observed after modification. The catalyst acidity was strengthened and acid-base bi-functional LDH catalysts can be obtained. The catalytic performance of these catalysts was tested on cyclohexanone self-condensation. The results show that cyclohexanone conversion rate of 85.7% and selectivity of 89.6% can be achieved under experimental conditions of 1.0 mol·L^-1 (NH₄)₂S₂O₈ solution, 140℃, 6 h and catalyst dosage of 5.0% (based on the weight of cyclohexanone). The catalytic activity of the succinic acid pillared S₂O₈^2-/Mg-Al hydrotalcites was better than that of LDH(5.6%) and succinic acid pillared hydrotalcites (53.4%). The novel succinic acid pillared S₂O₈^2-/Mg-Al hydrotalcite catalysts show good catalytic performance in cyclohexanone self-condensation and exhibit acid-base coordination processes.