Surface properties vs activity of meso-ZrO2 catalyst in chemoselective Meerwein-Ponndorf-Verley reduction of citral: Effect of calcination temperature

The catalytic transfer-hydrogenation of citral is a vital chemical process in food flavoring, fragrance, and pharmaceutical industries, that necessitates a high degree of purity of the product. However, the heterogeneous catalyst that is mainly selective to alpha,beta-unsaturated alcohol at atmospheric pressure is still lacking. Herein, we prepared a series of mesoporous ZrO2 via a soft-templated inverse micelle method, using different calcination temperatures 250-600 degrees C. The effect of the calcination temperature on the intrinsic surface properties of the meso-ZrO2 was revealed by analytical techniques such as N-2 adsorption-desorption isotherms, pXRD (powder Xray diffraction), TEM (transmission electron microscope), and CO2/NH3-TPD (temperature-programmed desorption). The meso-ZrO2 catalysts were compared in the Meerwein-Ponndorf-Verley (MPV) reduction of citral at atmospheric pressure. The meso-ZrO2 calcined at 350 degrees C presented a superior catalytic activity of 71% citral conversion and 100% selectivity to unsaturated alcohol after 10 h, under optimized reaction conditions. The superior activity is ascribed to the enlarged pore volume, increased surface area, and Lewis acidic sites. The calcination temperature has played a significant role in tailoring the surface properties of the meso-ZrO2, which in turn enhanced the catalytic activity. The meso-ZrO2 catalyst is recyclable, easily regenerated with simple calcination. The meso-ZrO2 shows excellent potential for industrial applications.

Automated summary

In this study, a series of mesoporous ZrO2 catalysts were prepared using different calcination temperatures, showing that the calcination temperature significantly influences the surface properties and catalytic activity of the catalyst, with the catalyst calcined at 350°C exhibiting the optimal catalytic performance. The catalyst demonstrated good recyclability and industrial application potential.