Pyrochlore/Al2O3 composites supported Pd for the selective synthesis of cyclopentanones from biobased furfurals

Designing a bifunctional catalyst with both highly selective C = O hydrogenation ability and Lewis acid-catalyzed ring-rearrangement ability is highly important for the synthesis of the cyclopentanone motifs from furfural derivatives. Herein, a class of pyrochlore/Al2O3 composites (2.68 wt%Y-2(Sn0.65Al0.35)(2)O7-delta/Al2O3, 7.74 wt% Y-2(Sn0.65Al0.35)(2)O7-delta/Al2O3) with a onefold Lewis acidity and rich oxygen defects were synthesized via a dissolution-precipitation method. After the impregnation by Pd nanoparticles, the oxygen defect of pyrochlore/ Al2O3 shows a bifunctional effect: they can adsorb C = O, promoting the selective C = O hydrogenation step and can enhance the accessibility of coordinatively unsaturated metal ions, providing Lewis acidic sites for the ringrearrangement step. The composite-based catalysts show noticeably higher hydrogenation and hydrolysis rates than their corresponding single metal oxide-based catalysts (Pd/Al2O3, Pd/Y2Sn2O7). Finally, 7.74 wt% Y-2(Sn0.65Al0.35)(2)O7-delta/Al2O3 shows a cyclopentanone yield of 98.1 % and a 3-hydroxymethyl cyclopentanone yield of 90.6 %. ATR-IR results verify the catalytic mechanism and emphasize the importance of oxygen defects.

Automated summary

A bifunctional catalyst based on pyrochlore/Al2O3 composites with rich oxygen defects was synthesized, showing enhanced C = O hydrogenation ability and Lewis acid-catalyzed ring-rearrangement ability. The composite-based catalysts demonstrated significantly improved reaction rates compared to single metal oxide-based catalysts.