Vanadium supported on titanium pillared montmorillonite clay for the selective catalytic oxidation of benzyl alcohol

Abstract

Mineral clays can contribute to chemical processes benign to the environment because they are low-cost and abundant natural materials. In the present work, a series of modified pillared clays (PILCs) were prepared from a bentonite and an acid pillaring solution containing titanium butoxide, subsequently were modified with different vanadium contents by wet impregnation. The characterization of these materials showed a significant increase in basal spacing, specific surface and pore volume of all pillared materials confirming the presence of pillars that expand the layers of clay. All the pillared materials were active in the oxidation of benzyl alcohol (BzOH) with H2O2 showing a high conversion of about 43% respect to the maximum, 95% selectivity to benzaldehyde (BzH) and 41% yield with V(0.5%)/Ti-PILC as catalyst, after 5 h of reaction. This catalytic performance might be related to the presence of highly dispersed isolated metal ions in tetrahedral coordination. Furthermore, V(0.5%)/Ti-PILC could be recovered and effectively reused during three cycles without a significant loss in its activity and with an approximate 1% decrease of selectivity.