Isomerization of α-pinene oxide to campholenic aldehyde in the presence of Al-SiO2 and magnetic Al-SiO2/Fe3O4 catalysts

In the present work, we demonstrated synthesis of Al-SiO2 and magnetically recoverable Al-SiO2/Fe3O4 systems via grafting of triethylaluminum on SiO2 and SiO2-coated magnetic Fe3O4 nanoparticles, respectively. These materials were characterized by various techniques including elemental and N2-adsorption/desorption analyses, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) using CO and pyridine as probe molecules. Amount of grafted Al on the support was found to affect the textural, acid–base properties and catalytic behavior in the isomerization of α-pinene oxide (PO) to campholenic aldehyde (CA). Maximal activity and selectivity towards CA was observed in the presence of sample with 12 wt% of alumina. It was demonstrated that 12%Al-SiO2/Fe3O4 can be used as catalyst for at least four successive cycles without loss of activity.