Palladium-Nanoparticles-Intercalated Montmorillonite Clay: A Green Catalyst for the Solvent-Free Chemoselective Hydrogenation of Squalene

Squalane is an important ingredient in the cosmetic, nutraceutical, and pharmaceutical industries. It has also been used as a model compound for the hydrocracking of crude and microalgae oil. Thus, a series of green heterogeneous metal catalysts were prepared to achieve complete hydrogenation of highly unsaturated squalene into squalane. Surface modification of the clay and metal intercalation simultaneously occurred during wet impregnation. The Pd-nanoparticles-intercalated clay with a dominating Pd(1 1 1) facet showed the highest reactivity and selectivity. The catalyst was stable with very low Pd leaching (≈0.03 ppm) and was recyclable without losing any significant catalytic activity. Play with clay: Metal (Pt, Pd, and Ni)-intercalated clay catalysts are prepared, and their catalytic activity in the hydrogenation of squalene is tested. The clay/Pd catalyst shows the highest catalytic activity and selectivity in the chemoselective reduction of squalene under solvent-free conditions, and this is attributed to the highly faceted Pd(1 1 1) plane. This catalyst can be recycled without a significant loss of activity.