KF on γ-alumina: An efficient catalyst for the aldol condensation to pseudoionones

摘要

KF/γ-alumina is an effective catalyst for the aldol condensation of citral with acetone. Even at a relatively low acetone/citral ratio of 1 -10, the selectivity to pseudoionones was high, ranging between 82% and 97%. X-ray diffraction shows the presence of KF and K3AlF6 crystallographic phases on the supported catalyst. At KF loadings of 3-6.75 mrnol g~(-1), a pretreatment of the catalyst by heating to 450 °C was necessary to obtain an active catalyst. However, samples with KF loadings of 8.5 mmol g~(-1) and higher were active even without pretreatment, facilitating handling and use of the catalysts. The development of (111) planes revealed by in.situ XRD during the thermal activation process correlates with the activity for aldol condensation.