Zr-based catalysts have been used extensively in catalytic transfer hydrogenation (CTH) reactions of the Meerwein-Ponndorf-Verley type, but can easily be deactivated in the CTH conversion of high concentrations of levulinic acid (LA) to γ-valerolactone (γ-GVL) become. . This work reveals that using cheaper glucose and ZrCl4th As two main raw materials, glucose phosphate carbamide zirconium (GluPC-Zr) can be easily synthesized on a large scale and at a low cost above a simple two-step conversion. The engineered GluPC-Zr has improved Lewis acid-base properties and good porosity and thus shows excellent activity for the CTH reactions of LA or its esters with isopropanol (IPA), resulting in 95-98% γ-GVL yields be achieved. Due to the excellent esterification performance of the acidic phosphate groups introduced, GluPC-Zr works well even at high LA concentrations and achieves a much higher turnover frequency (TOF, 8.2 mmol γ-GVL per g catalyst per hour) than previously reported catalysts based on Zr ( TOF, 0.2-2.4). And it shows excellent reusability in LA’s reaction with IPA that still delivers Approx. 95% γ-GVL yield after the seventh cycle run. This work provides a preferred esterification strategy for LA to prevent the deactivation of the catalyst, which is of particular importance for the large-scale production of γ-GVL from biomass-derived LA and an inexpensive GluPC-Zr catalyst.

Graphic summary: The transfer hydrogenation of highly concentrated levulinic acid to γ-valerolactone catalyzed by glucose phosphate carbamide-zirconium

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