Siberian Federal University

Two series of ZrO2-containing catalyst varied in textural and acidic properties were synthesized: 1) mesoporous composites on SBA‑15 (fabricated by co-precipitation and layer-by-layer deposition of Zr); 2) bulk ZrO2 (prepared by precipitation (monoclinic) and template method (inverse opals)). The catalysts were characterized by (TEM, SEM, UV and IR spectroscopy, XRF, N2 adsorption, pHpzc) and tested in levulinic acid to gamma-valerolactone conversion in a hydrogen-donor solvent – isopropanol, via hydrogen transfer by the Meerwein-Ponndorff-Werley mechanism. For ZrO2-containing catalysts based on SBA‑15, zirconium content and catalyst acidity turned out to be activity-determining properties. An increase in the catalyst acidity with a zirconium content reduction leads to a rise in the substrate conversion rate and a decrease in the GVL selectivity. The maximum GVL yield was 94 mol.% (190 °C, 120 min.) on the Zr/SBA‑15(2) catalyst fabricated by double layering of zirconia onto a mesoporous silica matrix. The activity of bulk ZrO2 turned out to be significantly lower, providing the maximum GVL yield 50 mol.% (190 °C, 195 min.) in the presence of monoclinic ZrO2.